A lot of science papers are like “we found a hint of this thing, we need to do more research” and it’s reported as “ALIENS??!?”
I understand why this is the case but I think it can lead to a loss in trust in science when the reporting jumps to conclusions that aren’t supported by the research itself.
In this case the abstract is far more grounded. In particular,
> The observations also provided a tentative hint of dimethyl sulfide (DMS), a possible biosignature gas, but the inference was of low statistical significance.
> We find that the spectrum cannot be explained by most molecules predicted for K2-18 b, with the exception of DMS and dimethyl disulfide (DMDS), also a potential biosignature gas.
> More observations are needed to increase the robustness of the findings and resolve the degeneracy between DMS and DMDS. The results also highlight the need for additional experimental and theoretical work to determine accurate cross sections of important biosignature gases and identify potential abiotic sources.
I think you have misread the abstract. The 'low statistical significance' was a [prior work](https://iopscience.iop.org/article/10.3847/2041-8213/acf577). This paper has increased the significance to 3-sigmas which is on the lower end but still quite significant.
Ugh, "alien life" is a reasonable title, IMO. I think the sensationalism is happening in your head, that you're imagining the Borg or little green men.
I don’t think it’s an unreasonable title, but it’s also not accurate. The paper states quite clearly that they’ve found reasonable evidence of a known biomarker. They don’t know enough to say whether it’s from a biological or some abiotic process (but speculate a little about what that might mean and what evidence they would need to take that further).
That’s quite a different tone from the article, and I think the comments here and elsewhere online reflect that.
I'm not convinced about the methods. It looks a lot like p-hacking to me: they have a highly specific hypothesis drawn from a large universe—that dozen or so molecules (§3.1) in their infrared spectrum model they're fitting experimental data against. I don't buy the way they created that hypothesis. The put a handful of highly specific biosignature gases into it, things that were proposed by exobiology theory papers. One very specific hypothesis out of many, and a low likelihood one. And that's the hypothesis they get some borderline ~3σ signals for? Really?
edit: Any chance someone might have the charity to explain why my criticism is so far off-base, according to the HN consensus?
I'm going to double-down on my stubborn, unpopular opinion. This is my best attempt at explaining my criticism:
- Alien metabolites are a low-prior probability hypothesis. Dimethyl sulfide is a long-postulated biosignature with no natural source, so, it's low-prior
- The paper's model fits Webb data—a handful of photons—against no more than 20 candidate molecules, combined across all of their atmospheric models. Many of those gases are drawn from that low-prior "alien metabolite" class
- There's a much larger class of strongly infrared-absorbing gases, that can naturally occur in planetary atmospheres. Beyond those included in the 20 candidates. These (should!) have higher prior probability of occurring in Webb data than alien metabolites. (This class is so large and complicated, there's major spectral features in our own solar system's gas planets we haven't characterized yet)
- If you were to fit Webb data against that expanded class, those alternative hypotheses, you'd get a large number of 3-sigma detections by pure chance.
- The Webb data is too weak to distinguish between these. With only a few bits of information, you can distinguish between only a small set of alternative hypotheses
- This paper elevates the alien-metabolite hypothesis very highly, and that is why when it has a spurious statistical detection, it happens to be an alien metabolite detection. Because that hypothesis is overrepresented in their model
- The root problem is that since there's only a trickle of real data from this exoplanet, from Webb, it's unlikely one can infer anything super interesting from those few bits
False positives are acceptable if the goal is to generate leads to follow up on. If the detection was due to chance then it won't hold up to further measurement. There's few enough hits that we don't need to worry about being more rigorous (and potentially introducing false negatives) at an earlier stage.
Given the context, a publication seems appropriate. A high profile similar example is when neutrinos supposedly broke the light speed barrier. If the mass media misrepresents things that's hardly the fault of the scientists.
Don't be bothered by the down votes. HN consensus is not something worth pursuing. Your criticism is valid, it's just that it runs against what HN readers want to believe in this instance. Readers here like to think they're motivated by reason and intelligence and whatnot, but that is laughable - examples of logical fallacies and assertions of fact rocketing to the top comments abound. Overconfidence and readiness to accept bold claims is a more dangerous cultural dysfunction than the lack of seriousness and ubiquitous monetization that plagues other platforms.
In any case this study will likely go on the pile of papers judged by time to be an overreach of conclusions and a dead end.
only know to be produced.....is a whoa bessy phrase,?¿ as in 70 years ago an undergraduate figured out that dimethyl sulfide was produced by living organisms and he asked his professor what else made it, and got shrug and "nothing else I know of" and everybody has been cutting and pasting since, OR, an international team spent years and millions working on the chemistry behind
dimethyl sufide in an epic known to all quest to determine it's origins.
Science does have an issue with cutting and pasting ancient mistakes, and then bieng exceptionaly reluctant to change and move forward,
not to mention that SETI, and the rest of "alien" research is most definitly tainted with public fantasy and entertainment industry influence, so
even with one of the notoriously oderiferous sulfide compounds present, I wont hold my breath
And the question is even more complex: not whether producing dimethyl sulfide "from scratch" without involving living organisms of the familiar sort is possible (of course it is), but what the hypothesis that each of the numerous possible ways to produce dimethyl sulfide happens naturally (or that alien lifeforms want a lot of it) implies about the environment of the exoplanet.
"...Although the chemistry of DMS beyond Earth is yet to be fully disclosed, this discovery provides conclusive observational evidence on its efficient abiotic production in the interstellar medium, casting doubts about using DMS as a reliable biomarker in exoplanet science..."
But in a concentration sufficient to be visible from this far away with spectroscopy?
It's not definitive but it is suggestive. A detection would require multiple pieces of evidence. We should be building specialized space telescopes designed specifically for the characterization of extrasolar planet atmospheres, since that's the best way we have to potentially detect something.
Firstly that is completely badass science. The idea that you can use observations to detect the chemical composition of an exoplanet millions of kilometres away is an absolute triumph of the work of thousands of people over hundreds of years. Really amazing and deeply humbling to me.
Secondly, my prior was always that life existed outside of earth. It just seems so unlikely that we are somehow that special. If life developed here I always felt it overwhelmingly likely that it developed elsewhere too given how incredibly unfathomably vast the universe is.
If life is very common in the universe, then that is probably bad news for us. It means that civilizations should exist that are millions of years more technologically advanced than us; and should be leaving telltale signatures across the sky that we'd likely have detected by now. And the absence of those signs would be relatively strong evidence that life, while common, isn't long-lived. Suggesting that our demise too, will come before too long.
If, on the other hand, life is relatively rare, or we're the sole example, our future can't be statistically estimated that way.
It is quite plausible that life is abundant, but sentience is not. If we take Earth, it formed 4.5 billions years ago, conditions became suitable to support life like 4B years ago and first known signs of life are dated 3.7B years ago.
Now, in just .5B years Earth would likely become uninhabitable due to Sun becoming a red giant. In other words, on Earth life spent 90% of its total available time before sentience emerged. So on one side life is constrained simply by time, and on the other, sentience might not be necessary for organisms to thrive: crocodiles are doing just fine without one for hundreds of millions of years. To think of it, it is only needed for those who can't adapt to the environment without it, so humans really might be very special, indeed.
Being intelligent doesn't necessarily lead to runaway technological development. Dolphins are smart but they're never going to invent radios to broadcast their existence to other star systems. They're stuck in the water and don't have thumbs. And even orangutans, who have thumbs and live on land, don't seem tracked for technology even if humans weren't around; their ecological niche is small even if we assumed humans weren't wrecking their environment, and they seem comfortable and steady in it.
Humans have been just as smart as you and me, maybe even smarter according to cranial measurements, without inventing anything that significantly changed their way of life.
There could be loads of planets with prehistoric humans, having a fine time hunting with bows and picking fruit.
I think by the time we get to modern humans it would only be a matter of time for technology to develop to something like the current stage. The main evidence I can think of is the independent development of agriculture in about 4-5 regions, and the independent development of large complex civilizations in the Americas and Eurasia.
Humans are cultural learners, so this allowed cumulative cultural evolution from at least as far back as the transition from Olowan to Acheulean stone technologies with Homo erectus ~2-3 million years ago. By the time we get to Homo sapiens and Neanderthal this capacity for cultural learning seems much increased. Some paleoarchaeologists (e.g. Dietrich Stout) argue that technological development has been exponential as far back as H. erectus, just that the early stages of the exponential curve look flat for a long time.
I think it only takes a small tweak for everything to stall.
Suppose say, that people only trust a small group. Extended family and lifelong friends, for instance. People get very violent as soon as they disagree on something, immediately wanting to settle disputes by force.
Nobody can strike a deal to do anything with anyone outside their group, and you certainly can't make agreements with a guy in Seattle to deliver things to London. You can't mine coal hoping to sell it to an as yet unknown person. There's no point in fishing more fish than you and your friends can eat.
What happens in this world? Well, I think people will still be intelligent. They'll still think about social situations, especially when it comes to mating. There will still be stories, and humor.
But we're not advancing tech, and we're not changing economically.
Why do I say it's a small tweak? Well, we've all met people who seem to not be able to work with anyone. It's not unlikely that out in the stars, there's some planet with people who have everything we have, but they can't get things to work.
Mutation is random but selection is non-random. Multilevel selection could select against those scenarios you're talking about. Collaboration could be yet another thing that comes from convergent evolution.
Random walks only progress if they don't get trapped in a local minima. GP example is but one entirely contrived scenario. The point is that technological development depends on many factors and it's entirely plausible that some of them aren't strongly selected for.
This seems to be supported if you consider how long it took for humans to emerge and the fact that other fairly intelligent species exist alongside us but didn't follow the same path. If you suppose that technological development has a clear selection path then why isn't there any evidence of space fairing dinosaurs?
Humans only started planting grain about 12k years ago. Anatomically modern humans were gathering wild grain, but not planting grain, for about 100k years. Given this very long period of stagnation, I don't think humanities ascension was an inevitability.
I know about the Natufan culture gathering and processing grain with grindstones from about 20k years ago, but don't remember anything from 100k years ago. Were they using grindstones to process grain? I'd have thought grass grains wouldn't be a good food source otherwise.
In any case, the seeming stagnation is part of what I meant by the early part of an exponential curve looking flat: broadly it might look like not much is happening, but there are small changes all the time.
Lack of evidence is also a problem when looking that far back: we have little concrete evidence of what these people were doing with wood, fibres, and other perishable materials.
Having said that, archaeologists used to talk about a "cultural revolution" that happened 20-30k years ago. (Maybe they still talk about it, I just haven't looked at the research recently). This was the period of the famous Lascaux cave paintings and what looks like an explosion of greater complexity in tool assemblages. So it's possible there was some rare cognitive leap at that time, or again it could be that we lack the evidence that would show the more gradual progression.
We really are pretty lucky that the industrial revolution happened. Thank god for England running out of trees to heat homes with, and abundant surface coal on that island.
I don't think so, though. I think that unless there are limiting factors (no ores or some other necessary component) life would tend toward technology.
Curiosity as an evolutionary trait is quite an advantage, and I would think is necessary for intelligent omnivores. It's what helped us figure out what we could and couldn't eat, and taught us better techniques for living. Curiosity naturally leads to technological developments, I would argue.
Lots of animals have been curious for hundreds of millions of years, but technology more advanced than breaking bits off rocks and sticks has only been around a couple thousand years. If you say it's a "natural progression", you also have to say there are serious barriers that most species will never pass.
So the notion that "life would tend toward technology", charitably speaking, does not make any useful predictions. Based on all evidence available, including the dearth of extraterrestrial technosignatures, you can't rely on it happening in any particular situation or timeframe. At best it's speculation, more likely it's just false.
> Dolphins are smart but they're never going to invent radios to broadcast their existence to other star systems.
How could we possibly know this? The only case of "Dolphins" we know of, is on Earth, with the interference of humanity, and we're looking at Dolphins at a really small timescale.
Given N thousands of years without interference from other species, who can really confidently tell exactly how Dolphins would evolve?
We've had at least two developments of ""dolphins"" that I know of. We also have other intelligent sea life, like squids and octopuses, who've been around for a hell of a long time and are on track to never develop advanced tool creation and use. Living in the water is a massive tech nerf.
Notably the latter example has ideal appendages for tool manipulation - likely far superior to primates with thumbs. Yet somehow they're indefinitely stuck without tool use.
I wonder if things would progress if they had the same level of communication that dolphins do.
Again, are you saying that you confidently can predict a hypothetical future where Dolphins, even given millions of years, would never invent the radio? I think it's unlikely too, but so are humans, so who knows what could happen.
Living underwater puts a dampener (didn't intend this atrocious pun, sry about that) on any technology that depends on fire. So smelting ores seems out of the question, and of course radios are made out of lots of pieces of metal.
I can't think of any plausible ways a water-bound species would be able to harness and use electricity either
Besides the whole fire thing, which is a serious problem for the metallurgy necessary to make radio, to have any chance of it they'd need to get fingers instead of the optimal swimming flippers they have now. They'll never do that as long as they're aquatic. If millions of years of evolution has them climb out of the water and become land animals again then there might be a glimmer of hope for them, but then they'd no longer be recognizable as dolphins. As it stands now, field mice have a more direct path towards becoming radio makers than dolphins do.
Nevertheless, if abiogenesis is common & intelligence is easy for evolution conditional on abiogenesis, the number of explanations for the Fermi Paradox just shrunk by a great deal, increasing the probability of the remaining explanations.
I doubt there is one single grand answer for the Fermi Paradox. Probably it's lots of smaller blockers which all stack up with each other. The chance of life forming, the chance that it becomes multicellular, the chance that it develops complex nervous systems, intelligence, the physiological hardware for tool use and creation, not stagnating or getting wiped out, having the inclination to look out and broadcast their existence, the chance that they survive long enough while doing this to exist at the same time as another civilization of comparable development, etc. It's easy to come up with these and even if they all have modestly small probabilities each, together they stack up to a plausible answer to the so called paradox.
The paradox would remain valid in my view. Even with all those stacked difficulties and plausibility levels, the galaxy alone is immense and if life of any kind were to be found, i'd argue that we should be able to see signs of sophisticated life somewhere at least, so where is it? It's still a cause for some speculation and maybe even existential worry.
The galaxy isn't really that huge. 10e11 stars. If you stack only a dozen obstacles at 10% odds of overcoming them each, you come up with advanced radio-broadcasting life being an unusual outcome for a galaxy our size. Add a few more and you can bet against another advanced civilization coinciding with us in the entire observable universe.
They'd still be dolphins in the same way that you are still a fish.
Also, I don't think you're right that they could do this easily. Their hind limbs have almost completely vanished, their pelvis too, and they have no chance of moving on land. To have a chance they would need to redevelop those things which they've lost, and I don't think there's a particularly plausible path where each step helps their survival at that step. In contrast, their four-limbed land adapted ancestors could swim much better than dolphins can walk.
You confused two things. There is the Sun turning into red giant in 5 billion years consuming the Earth, and the Sun getting too bright for Earth to be habitable in 500 million years.
While it has more time to become a red giant, it'll become more luminous over time and life on Earth will be impossible much earlier. I've seen estimates of 0.5B to 1.5B years.
That's not the point: if you have capabilities to do stellar lifting, interstellar travel is likely on the table too. Fermi paradox is about the question, why we can't detect any sign of extraterrestrial civilizations out there. One explanation is that while life in general might be relatively abundant, true sentience as in us humans that allows life to spread besides its cradle might be quite unique.
In 500 million years, hopefully humans (or whatever humans have become at that point) will be able to modify the Earth's atmosphere to deal with the increased luminosity of the Sun.
We might be lucky enough to do that, but it could have easily taken intelligence another 500M years to evolve on another planet. First animal fossils are something like 700M years old, so it took 2-3G years to just any animals.
The problem is that there are just so many planets. Sure, another planet could be 500My slower, but with a billion planets, some of them should be 500My faster instead.
It's possible we are absolutely one-in-a-billion uniquely lucky - after all, someone has to be the first and the luckiest. But every year we find indications that our planet is completely typical.
We'll have colonized the galaxy in 10 million years. In 200 million years, I'd expect that some future historical society could undertake a project to clean out the heavy elements in the Sun to keep it going.
Yeah, but if humans exist by the time the sun fails us, they wouldn’t really be the same species as us, and they’d hopefully have progressed to the point that they could escape the Earth.
You're saying we wont maintain tradition and our "humanity"?. I like to be a little more optimistic and believe in us as a species transferring values until the end.
Look at all types of mammal that exist, from us to platypuses to bats to whales. Evolved in a few hundred million years. Modern humans have been here for a few hundred thousand.
In 500 million years absolutely anything could happen (if we survive this century).
The lower end estimate depends on the specifics of the increase in brightness accelerating the weathering of silicates, leading to more CO2 absorbed out of the atmosphere until C3 photosynthesis isn't possible. Some plants use a different method which will continue to work (C4), but consequences of plant life as we know it dying off would be catastrophic for life on this planet - barring of course, whatever adaptations are made.
But it's certainly the mark of "the beginning of the end" for life on this planet - it's a major milestone that we (the species) do need to leave eventually if we want to continue.
Every field of study, subject, or problem, or even business cases, -- all have different ranges.
Why does this one in-particular sound like they don't know what they are talking about? It would be just as accurate for me to say in the range of responses, yours kind of sounds like an anti-science bot. Typical of that type of thinking.
The difference between .5B years and 1.5B (BILLION) years is pretty staggering in a conversation basically focused around the last couple thousand years. Definitely room for the comment.
Your anti-science bot comment however, is very anti-science.
Really? With the age of a star, that is too wide a range for you to accept? To pinpoint something like this. What if I were to say, "really it's 1.3435 Billion on a Tuesday".
Of course, calling someone anti-anti-science. The new 'right'. Using science arguments against science. Yes. Your comment is typical, just spam fud. "look at this huge range, see, scientist don't know what they are doing"
Earth is on course to become uninhabitable for human civilisation its current form within a century, with an associated mass extinction.
Even if all industrial activity stopped tomorrow there's now enough CO2 in the system to guarantee a succession of uncomfortable and expensive droughts, floods, storms, and wildfires for thousands of years.
If it doesn't they will become more and more extreme very quickly.
If ocean acidification and warming destroy the foodchain in the seas, collapse on land will happen very quickly.
Did you notice that you aren't wrong because you're not really saying anything at all? "in its current form" - so maybe with slightly different distribution of land use but basically fine and not necessarily as different as today is from 50 years ago? "mass extinction" already been happening for ages for many species. "uncomfortable floods/etc?" Already been happening for all of history. "very quickly" is how quicky? "more extreme" is how much more extreme?
> so maybe with slightly different distribution of land use but basically fine and not necessarily as different as today is from 50 years ago?
No, probably very much more different than that, more like rolling back on industrialisation and globalisation. Closer to 500 years than 50, without the same hope of "progress" that we had back then.
> "mass extinction" already been happening for ages for many species.
Yeah, we all learned about dinosaurs when we were little kids, but if humanity collapses there's no guarantee of anything similar developing after us.
Maybe once day, aliens will drop by and discover what remains of humanity. And stories will be told of how, when the time came, our species decided to bury its head in the sand and hope the problem would go away. Or maybe that we attempted to create god to come rescue us.
Life imitates art. We refused to listen to the scientists.
Why do you think aliens will drop by? If aliens were visiting every planet in the universe, don't you think we would have noticed that by now? I mean, why didn't they visit the solar system and colonize it (and everywhere else) aeons ago?
I owned quite a number of pets in my life, so I don't need explaining that they do have some kind of relatively high-order intelligence that allows them to do quite a lot of things. Yet, this is clear that no kind of animal on Earth but us exhibits potential to have capabilities to spread themeselves beyond home planet once it becomes uninhabitable. Moreover, signs show that once a type of species finds their niche, their intelligence levels off and does not tend to increase. In other words, modern crocodiles are no smarter than crocs from 10 millions of years ago, because they are doing mostly fine as they are.
Yes, I think GP phrased it badly. This is just about the meaning of words: "sentience" just means sensory or experiential consciousness. It doesn't necessarily imply high intelligence or capacity for using technology
The fact that sharks have existed for 450 million years fairly unchanged fills me with hope. Our existence might be a huge fluke even if eukaryotic life can happen once and again in the Universe.
Technically, it is: https://en.wiktionary.org/wiki/sentient (the first two definitions). You mean the science fiction definition though (the third), and it's because it's not self-aware and not very intelligent, because it doesn't need to be to survive and procreate successfully. A slightly smarter crocodile must not have enough of an advantage over its peers to matter for evolutionary purposes.
Honestly, I do not think high-intelligence is useful for life. The most successful life forms aren’t the most intelligent, and humans seem to be fixed to self-annihilate.
what do you consider the most successful life forms to be? humans currently inhabit every continent and are unquestionably at the top of the food chain.
Are we though? Bacteria do better than us. Cockroaches. Rats. Ants. Grasses. Plankton. We aren’t the most numerous. We aren’t the most widespread. We are serious risk of killing off our own species.
If the Earth was about to be hit by a huge asteroid, some people might survive (by fleeing in spaceships) but none of the species you list have a chance unless people choose to save them.
I highly doubt much of the bacteria would care. The amoeba probably wouldn’t either. Also, rodents have already survived such impacts. All mammals alive today are alive because our ancestors didn’t die with dinosaurs.
If the Earth is completely destroyed, the humans on space ships wouldn’t survive either. There is no self-sustaining off world colony currently, and there most likely will not be in the lifetime of anyone alive today. At such time that there is, bacteria, rodents, and other life will likely come with humans as humans build the biospheres that we need elsewhere.
You seem to be conflating life, multicellular life, and intelligent life. Life appears to have developed on Earth pretty quickly, multicellular life took a long time to appear, and we are only aware of one species that developed civilisation building capabilities.
Life might be very common, but intelligent life still be incrediblY rare.
It depends what you mean by "civilization building". I think we gloss over that a bit too much. We're not the largest population, not the largest total mass, not the only one that builds large structures. We're the only one that sent stuff outside of Earth, yes, and a few other things. But discussing the definition is itself interesting
Human civilisation means intelligence and memory are collective, externalised, persistent, communicable. There's also a layer of symbolic abstraction (science and math) which makes it possible to predict useful consequences with some precision.
Individuals die but their inventions and insights remain. Individuals can also specialise, which is a kind of civilisational divide and conquer strategy.
Most animals don't have that. Some do train their young to a limited extent, but without writing the knowledge doesn't persist. And without abstraction it only evolves extremely slowly, if at all.
They have to reinvent the wheel over and over, which means they never invent the wheel at all.
We actually have this problem with politics and relationships. We keep making the same mistakes because the humanities provide some limited memory, but there's no symbolic abstraction and prediction - just story telling, which is far less effective.
Bonus points: I often wonder if there's a level of complexity beyond our kind of intelligence, and what it might look like. Abstraction of abstraction would be meta-learning - symbolic systems that manipulate the creation and distribution of civilisational learning.
AI seems to be heading in that direction.
There may be further levels, but we can't imagine them. We could be embedded in them and we wouldn't see them for what they are.
The only similar example I can think of is when, roughly 2400 million years ago (during the Paleoproterozoic iirc), the ancestors of cyanobacteria poisoned their atmosphere by overproducing oxygen which resulted in an extinction event. But that whole process still took somewhere in the order of millions of years to complete I believe.
> But that whole process still took somewhere in the order of millions of years to complete I believe.
The geological evidence is that that oxygen build-up first had to exhaust things that took the reactive oxygen out of the air and water. Iron oxide was laid down as huge deposits of "banded iron ore" The great rust. (1)
This is hard to get an exact number on, but as far as I know, it is estimated to have taken at least 500 million years.
And then oxygen increased again, a billion years later (2)
It was not fast. It was measured in 100 million year ticks.
>we are only aware of one species that developed civilization building capabilities.
well, the first one just doesn't leave any chance for any other one.
>Life might be very common, but intelligent life still be incrediblY rare.
the time period between big ape and nuclear bomb is extremely short - few millions years. In a hundred or a thousand - doesn't really matter - years we'll be an interstellar species or may be we destroy ourselves by Covid-2319. The point is that complexity develops exponentially and tremendous changes are happening in an extremely a short period of time - i.e. if life has 4B years to develop when it most probably has 4.01B years to develop civilization.
Unlikely we will ever be interstellar. The technology involved is speculative and the physics barriers needed to be surpassed are impossible and not well understood.
To reach another star by the laws of physics involves many human lifetimes and that’s just the nearest star.
That in itself makes it more likely that we will never be interstellar.
Slow but plausible starships can be designed with 1960s technology. The obstacle is not the technology but the scale of the effort, a problem that could be solved by extension of civilization into the solar system with much larger populations.
Humanity will never put effort into this. We don’t have the technology yet but yes we can develop it but doing this is harder than building a bridge across the ocean between Asia and the US.
That bridge is also within our technological capacity. But it’s not happening period.
That depends on the scale of human society, doesn't it? Grow the population in the solar system enough and it becomes a smaller fraction of gross output than many trivial and frivolous things are today.
I'm arguing here that if non-interstellar space colonization is possible, interstellar colonization is a natural and feasible extension. You might argue that even colonization in the solar system will not occur, and I admit that's a defensible position.
>The technology involved is speculative and the physics barriers needed to be surpassed are impossible and not well understood.
we can build with today's tech - classic nuclear reactor plus ion drive - a 3 stage ship reaching 1000km/s, 1200 years to the closest star. Once we get to fusion, we'll be able to improve that speed a small order of magnitude.
>To reach another star by the laws of physics involves many human lifetimes and that’s just the nearest star.
>That in itself makes it more likely that we will never be interstellar.
That is exactly what makes it _inter_stellar:) We'll have generations - 10-15 to the nearest star with the current tech mentioned above - of people living their lives on those ships. Living on a planet will become a strange thing for them.
I think in 10-20 years, once launching into LEO becomes cheap with Starship, companies, universities and wealthy individuals will be launching solar + ion drive and nuclear + ion to all the places in the Solar System and some automated probes - beyond.
Intelligent life most like arose from the extinction level events that wiped out less intelligent super predators. This gave those who are far weaker but with higher brain capacity the chance to express their genetic variations.
Not to take away from you personally, but civilization as we understand it is our own cliche.
Organisms developed on different planets could absolutely have a different view on life and society in general. Even on earth we have highly intelligent and physically capable organisms that care naught for your conceptions of how groups should function together. There are even organisms that seem to have no intersection with our set of interests that are way more successful in terms of populating earth and invading space. Putting our understanding and interests at some panacea is just hubris.
I was just watching the original (first) matrix movie yesterday because I was just too bored.
And there was this dialogue by Agent Smith:-
```I’d like to share a revelation during my time here. It came to me when I tried to classify your species. I realized that you’re not actually mammals. Every mammal on this planet instinctively develops a natural equilibrium with the surrounding environment but you humans do not. You move to an area and you multiply and multiply until every natural resource is consumed. The only way you can survive is to spread to another area. There is another organism on this planet that follows the same pattern. Do you know what it is? A virus. Human beings are a disease, a cancer of this planet. You are a plague, and we are the cure.```
So yea, I totally agree with you because just as how Agent Smith compared Humans to a virus and just like we know that not every living thing is a virus,
In a similar fashion, I think not every species have intersection with our sets of interests (populating earth,invading space).
I actually had just watched matrix for agent smith actually. I don't know why but the guy looks really cool to me for some reason.
It's a cool speech, but it's also wrong. Mammals don't "instinctively develop a natural equilibrium", reality forces that equilibrium on them. A species gets too good at breeding and/or resource consumption - that's either happy times for their predators who eat them back into balance, or they starve themselves back into balance.
I mean game theory and equilibria are universal. I don’t see why the basic rules of civilization would not apply to any level of organism sophistication.
Maybe technology development is not exponential but s-curve. And anything large scale is impossible. So outside some radio signals there would not be any grand things that could be observed.
This is where the discussion, as it always does, silently transitions from science into science fiction.
We know absolutely nothing about extraterrestrial life. We can only project our own singular experience onto the rest of the universe. We only have one data point. There is no scientifically acceptable method of induction from a single data point. The possibilities are endless, and are capacity to narrow them down becomes warped by our love of stories and the kinds of art that we have created about extraterrestial life, all of which are in one way or another metaphors for the human condition.
There is nothing wrong with saying, "Anything is possible and we have 0 evidence allowing us to narrow it down." It isn't fun, but it's true.
Dark forest hypothesis explains this in a “dark” way. They exist but are smart enough to hide from hostile hunter/predator life forms. Meanwhile our dumbasses are blasting radio signals into space like a little kid trying to talk to every stranger they see.
Dark Forest depends on the presumption that interstellar travel is worth engaging in (ie it's possible to do faster than light), and that spectacularly devastating weapons are possible. So far we have no reason to believe that either of those assumptions is smart.
Faster than light travel isn't needed (and IIRC doesn't occur in the series the dark forest name comes from). Spectacularly devastating weapons are definitely possible - redirect an asteroid into an inhabited planet and you're likely to kill most of its inhabitants; redirect enough and you can kill almost everything. That's not even getting into things like antimatter, gamma rays, etc. The dark forest hypothesis doesn't need destruction of solar systems to be possible, just severe damage to civilisations.
Ah, yes, you are right. They managed to speed up their travel time to Earth greatly, but they did not reach or surpass the speed of light. I have to read the trilogy again.
They had the sophons which allowed them to convey information via quantum entanglement, i.e. instantly.
They - and the humans - developed close to light speed traveling which IIRC has the same underlying mechanics as that blackout-galaxy-safe-space thing which is the message that your civilization is not harmful.
It's also largely bunk. More a story than a hypothesis, really. Game theory shows cooperation beats aggression on a long enough timescale. Politics shows alliances and MAD deters first strike. Even actual "dark forests" are full of animals that have bright colors and make loud noises.
The Indigenous peoples of the Americas knew well enough about the value of cooperation and alliance. That's why they had stuff like the Iroquois Confederacy, and switched between working with the British, the French, and the colonies depending on which was best for each individual group of natives at any one time. To present them as pure victims powerless before the might of white settlers undermines the political and cultural agency that Native peoples in fact had, and exercised.
The predominant form of relationship between European and Native American peoples for hundreds of years was trade, not war. The tragedies and the atrocities that resulted were a slow burn of conflicting interests and epidemiological naïveté, both between Europeans and Natives and also within each group. That's quite different from the hiding and decapitation strikes usually presented as "dark forest hypothesis", because there's no reason that those specific interests and ignorance would carry over to interstellar society (and every reason that they would need to be overcome in order to become interstellar in the first place).
But why do people always use the fate of resource-constrained preindustrial societies (both Europe and America) to try to predict relationships between hyper-advanced Kardashev-level civilizations anyway? It really seems to me like some kind of projected shame. You can see this too with Liu Cixin. He came from a country that was recently dominated, and has more recently been preparing to dominate its neighbors, so his story pretends nothing better is possible. I suppose that's comforting for some, and questioning it brings out people who show what it's really about.
Google Trends shows the top 10 countries for "Dark forest hypothesis" include the US, Taiwan, China, Peurto Rico, HK, Canada, and Aus [1]— Places with a prominent recent or ongoing imperial history, whether as victims or victimizers. I actually find the "dark forest" narratives quite disturbing, not as a prediction of our future, but as a window into the psyche of people who seem to want it to be one.
You might as well say the Romans had a slave-based economy, so therefore spacefaring empires must also be looking for human slaves! That's got exactly the same amount of validity as the Native comparison. But economic and military incentives obviously change as technology and culture develops. If anything, the fact we used to kill a lot of natives, and we don't so much anymore, is a strong sign that advanced societies can trend towards being less genocidal.
Valid arguments tbh. In the struggles between European and Native American, there is the aspect of being able to escape and continue to pose as a threat and such. There is no total extinction. But in dark forest theory there is the total extinction of home planet aspect, without giving in your own location (no vengeance or kill switch can be carried towards you). And also attack factor being so much more advanced that there is little to no defense against it.
In our world, we never had this level of capability amassed in one hand. We were never tested in this scale. But lets think there was a button in cold war that completely erased soviets with no harm to planet, no harm to the western world and without anyone noticing the origin of this action. How many in U.S. would press that button? I think we would've pressed many times. And later, to know that another planet might be having a button exactly like this that they can press and erase us? we would press first so they never get the chance to do it. Paranoia and self preservation prevails, sadly.
I believe our cooperation in society also relies on our capability of projecting power be it physical or economical. The weaker individuals power becomes, the louder powerful peoples actions become. Saying this as Non-U.S citizen, right now the richest guy can easily interfere in state dealings, act like the president in a way, maybe this is evolution of lobbying tradition there but could you imagine such a thing happening in ancient Greece or even in Rome? What prevented this was citizens' ability to exert power. Right now there is little of that, power disparity is huge and so there isn't as much of a cooperation. Sorry if this part deviated from topic or smth. It is just I believe it 100% depends on real, physical factors rather than how advanced we get mentally.
Cooperation depends on you and your potential allies surviving long enough to be able to contact each other, and being strong enough to counter the threat. We don't know whether we will develop capabilities fast enough to counter an enemy that e.g. at the first sign of radio started accelerating a bunch of super-dense (hence small, hard to detect and stop) kinetic kill devices our way.
MAD is utter bunk. It depends on rational actors that also believes the other actors are rational. Even Reagan realised the folly of MAD after Able Archer in 1983, and realising the Soviet leadership genuinely seemed to believe the US might be prepared to strike first. If either side thinks the other side is irrational and preparing a first strike, MAD falls apart. If either side is actually irrational, it also falls apart.
But MAD also depends on a sufficient ability for both sides to do serious harm. If one side sees a first strike as an opportunity to prevent the other side from gaining that ability, MAD also falls apart, and the thinking behind it can again then push a rational but callous actor to strike first to prevent being pushed into a MAD scenario.
Cooperation might eventually win out, but that won't help you if your civilization has long since been wiped out.
Cooperation only depends on anyone, in the history of ever, having at any point survived long enough to contact each other and form an alliance. Once a critical mass of parties that prefer cooperation has been reached, all future cooperative parties are at an automatic advantage over aggressive parties.
You can see shades this of this, e.g., in the difference between single-round versus iterated Prisoner's Dilemmas.
> MAD is utter bunk. It depends on rational actors that also believes the other actors are rational. Even Reagan realised the folly of MAD after Able Archer in 1983, and realising the Soviet leadership genuinely seemed to believe the US might be prepared to strike first.
What do you think the long-term prospects are of a species that goes around flinging RKVs at people? No more North America and no more Eurasia, if that happened. Maybe South America and Africa can pick up the pieces. Just because irrational hyperaggressive actors can briefly exist doesn't mean you're likely to encounter them. They won't survive for long.
MAD exists whether or not any particular participant believes in it, because it's just the cause and effect of competing powers each with their own agency. Or else we wouldn't be here. Even the Soviets knew that a possible US first strike was better than a guaranteed US retaliatory strike, which would happen if they struck first.
> Cooperation might eventually win out, but that won't help you if your civilization has long since been wiped out.
The whole "Fermi Paradox" arguments are based on an extreme form of "eventually, we should expect to see aliens, so why haven't we already?" This doesn't mean aggressive civilizations don't exist, but the reasons to think they're prevalent are overblown.
> all future cooperative parties are at an automatic advantage over aggressive parties.
No, that does not follow, because it assumes any cooperation gives sufficient leverage to be able to resist. But an enemy lobbing kinetic kill devices at high speed from locations that does not give them away would require far more advanced tech to stop.
> What do you think the long-term prospects are of a species that goes around flinging RKVs at people? No more North America and no more Eurasia, if that happened. Maybe South America and Africa can pick up the pieces. Just because irrational hyperaggressive actors can briefly exist doesn't mean you're likely to encounter them. They won't survive for long.
On Earth. In space, throwing kinetic kill devices at people won't affect your own territory, and can at least in theory be done without any possibility of tracing it back to you - you "just" need to accelerate a bunch of them outward to starting positions far from your home system. Any civilization smart enough to be able to build devices like that would be smart enough to build autonomous ones that would become operatonal first when in a position that wouldn't give them away.
> MAD exists whether or not any particular participant believes in it, because it's just the cause and effect of competing powers each with their own agency. Or else we wouldn't be here. Even the Soviets knew that a possible US first strike was better than a guaranteed US retaliatory strike, which would happen if they struck first.
The point of the lessons Able Archer is that there were strong indications the Soviets thought there was a line at which point a first strike to preempt a US first strike would be preferable, and that they thought they were getting close to that line.
> The whole "Fermi Paradox" arguments are based on an extreme form of "eventually, we should expect to see aliens, so why haven't we already?" This doesn't mean aggressive civilizations don't exist, but the reasons to think they're prevalent are overblown.
I've seen nobody suggest we have strong reasons to think they are prevalent. That is missing the point. It's one of many possibilities, but one where the temporary existence of even one in any given "neighbourhood" close enough to strike before we've gotten advanced enough to defend against compact kinetic kill devices hammering us at a decent percentage of c (or worse options we don't know about) would mean we'd already be doomed without knowing about it.
It doesn't even need to be a long-lived one. There just need to have been one alive when our first radio signals hit them.
It doesn't even need to successfully kill most civilization. For it to resolve the Fermi Paradox, attacks just need to happen often enough that those who survive quickly decides hiding is the best option just in case.
I often wonder if the answer to the Fermi paradox isn't just as extremely banal as "turns out that interstellar exploration just isn't economically viable". I think it's entirely plausible that advanced economies are circular, and that within a circular economy, it's just extremely difficult to justify the massive expenditure of resources that it would take to become interstellar.
I mean, think about how many stars had to align to catalyze our first steps on the moon. Now, 53 years later, we're just starting to put serious effort into going back -- not because there's any market reason to do so, but because (once again) there's political pressure for it. Which would suggest that the best case scenario for the current exploration efforts are something along the lines of what we already see in Antarctica: a well-staffed scientific presence that does really cool/valuable work, but nothing remotely approaching even a single major city in terms of human presense.
It seems to me that one of the unwritten priors to the Fermi paradox (at least in popular discourse) is that technology is the only prerequisite to expanding a civilization; in other words, if you have the technology, then interstellar expansion is only a matter of time, and that all civilizations will inevitably eventually develop the technology. And that... seems like a pretty big assumption, if human history is any indication.
The thinking generally would be that while it might take political pressure to initially begin leaving the home planet, once politics has unlocked that capability, commerce will take over.
If we were to begin mining the solar system, it unlocks vast pools of resources that would really change things.
That said, interstellar travel is still a pipe dream because of the time involved. Without finding a cheat code for physics, it may well be that intelligent life is always trapped in its home system and has to live and die within the limitations of stellar evolution.
It seems, at present, that energy is more of a constraint on civilization than matter.
With unlimited cheap energy, there's enough material to do most anything we might reasonably want.
It's likely to cost $thousands/kg to bring materials back from beyond Earth orbit. There are only a handful of elements valuable enough, and that's if they existed in pure form.
Hypothetically, if an asteroid made of pure gold existed, and if a Cargo Dragon atop a Falcon Heavy had enough delta-V to make it there and back with a couple of tonnes, it might break even, but all of this is doubtful.
Most valuable minerals are worth hundreds to low thousands of dollars per kg, so you need a launcher that can bring back a ton of rock for $1M - and not from LEO, you probably need to escape Earth's gravity and get back again.
The physics and engineering are proven, but the economics? Unlikely.
Put another way, you can mine a heck of a lot of Earth rocks with a rocket's worth of kerosene.
I thought it might just be the rocket equation. Bigger planet = very little of the rocket is payload.
If most planets are bigger than Earth, then most civilizations will be like "muh we can do it but what's the point?" and they'll be content with just having a few science experiments in orbit, and that's all.
If life is quite common, that still leaves an option that we are among the oldest of civilisations.
Besides, lack of comical presence doesn’t necessarily mean demise: maybe all face the problematic consequences of uncontrolled industrialisation and go solar punk?
Even if civilizations are relatively common (which, as others have pointed out, doesn't necessarily follow from life being common), the distances involved are really huge.
We have some ideas for crossing huge distances, but none of them are really practical. There are ideas for accelerating tiny probes with light sails, but when we manage to send them somewhere with 90% of the speed of light, we have no way to decelerate them again in a controlled fashion.
What I want to say is: there's good reason to think that doing anything over 200 light years or so is just infeasible.
> And the absence of those signs would be relatively strong evidence that life, while common, isn't long-lived.
Stars are abundant, long-lived, and go through cycles of life and death.
Now look at the night sky. The chance that you eye will detect a star at any given patch of sky that is roughly the size of a star, is nearly nill. That is not bad news for those who wish to see that stars continue to exist - it is a feature of the size, vastness, and expansion of the universe. Same for life, presumably.
Scientists use the term "technosignatures", which you can google for more info. But broadly: radio signals, infrared from megastructures, optical signals like laser pulses.
We haven't put a huge amount of effort in searching for such signatures, but there has been some.
Another possibility is we're looking for the wrong techno signatures, or just haven't conceived what the technosignatures for a 10,000-year technologically advanced civilization are.
We've been a techno-civ for what? Maybe only 200-ish years? Our paradigm is gobble up all the energy and grow at all costs. So extrapolate that out, and the logical conclusion is a dyson megasphere that radiates all over the infrared.
But then again, that paradigm is careening us towards an environmental and ecosystem collapse: the hunger for infinite growth is warming our climate, it's unclear whether our nuclear-armed social structures can handle the coming disruptions and migrations, and if we don't kill ourselves, unclear how big a population all the environmental degradation and pollution can support.
So we can project our cute 200-year-old patterns out to a maybe-discoverable 10,000-year civilization driven by the same motivations and flows, but those extrapolations quickly run up against some pretty existential pragmatic threats.
Maybe the answer is we aren't seeing any of the technosignatures because the techonsignatures on the other side of the Great Filter look very different from the ones we conceive of now.
Thing is, though, it kind of assumes megastructures. AIUI Earth is already getting less radio-noise-y, as fibre-optics take over, and would be difficult for us to detect from the next star (at least to detect the technological civilisation; the biosignatures would be obvious).
Maybe people just don't _actually_ build that many megastructures.
I’m personally not convinced advanced civilizations would necessarily exhibit such technosignatures at all. I even go as far and ask are you sure if an advanced civilization was living and mining in Saturn’s rings we would even notice? If one considers the scales of things and realizes how big the Saturn system is relative to Earth then I doubt they can be so confident we would even notice our neighbors in the solar system yet.
no matter how advanced the civilization is, proxima centauri will always be 42 trillion kms away. Our civilization in current stage is not even close to 0.1% the speed of light but lets say your advanced civilization goes at 99% the speed of light, still doesnt change the fact they need 4.25 years approx to reach earth. Still doesnt change the fact that unless they have a 1 billion km wide telscope, they cannot reliably tell if earth has life or not. So basically you are asking them to take a shot at coming to the solar system on a 5 yr trip when they have no idea what is found here. Now extrapolate the numbers for the average 100 light year trip between 2 points on our galaxy and you ll quickly realize why we dont have aliens
On a similar note, humans cannot colonize the galaxy. Sending a single message across would take thousands of years. Instead a human ancestor would split into various individual species.
When you think of it, light speed is really slow. Even on Earth we are capped by it.
some calculation about resolution of the telescope to be able to see cities and people of another planet from a 100 light years away at the minimum. I forgot the exact calculation but it ll need a humongous sized telescope mirror
I always thought that how far things are in the universe and the impossibility of faster than light travel were enough to explain why life might be abundant in the universe yet we never observed it.
The probability of advanced civilization is given the probability of life is quite low itself.
For the overwhelming majority of time life has existed on earth only a minuscule part of it involved civilization. And an even more minuscule part of it involved technology that has a small chance to send a coherent signal to another star.
Our future is easily estimated by the hardness of traveling through space and the demise of our sun. Probability points to the end humanity by way of the death of our star. We are statistically most likely to end.
We don't have to look to the stars to tell that humans have a horrible tendency to make the majority's life a struggle and constantly balancing on the verge of demise.
Maybe they just don't feel the need to blast their emissions all over the sky like some sort of a caveman.
Our own technological signature is coming to form a very thin shell. Once we switch fully to fiber optics, lasers, and beamformers, there won't be any aliens learning English from listening in on our TV transmissions anymore. Radio broadcasting was cool, but also horribly wasteful.
It's probably incorrect to assume that more technologically advanced civilizations would be louder.
It's extremely likely that our demise will come before too long.
The problem is that "before too long" is on a universal timescale, not a human timescale.
Humanity could exist for a million times longer than it already has, expand to other planets in our solar system and even to another solar system or two, be wiped out completely, and on the appropriate timescale we were absolutely "short lived."
Life isn't this "magical" force.
Life is just an outcome which is just incredibly rare. Or maybe its not? Maybe we are just too primitive in the sense that we haven't analyzed all planets (like this planet is just 120 light years away, still huge but still, who knows how this search continues, and maybe we can even find more/maybe advanced species as well?
But also, as others have pointed out. I think that getting to civilisation level is pretty rare. Its not like the signs on this life that we have found automatically means that they are one day going to be a civilization level life. They may or may not & so many other comments above this comment have beautifully shown the amount of rarity in that which was the major takeaway from this HN atleast for me.
Its still just so fascinating how human societies exist. Maybe I am pessimistic, but like we believe in gold because everyone else does, but for the first time ever, Imagine the people who started trusting in gold and started trading in gold.
They couldn't eat gold, For all its worth, they might have thought that its just shiny rock and its abundant, we just haven't discovered it yet and its going to be worthless so we might as well use grains.
But such trust in gold,maybe even religion/ general trust on society structure beyond the people you know directly is just so bizarre.
People believing and dying for nations made those nations have power. And now we trust those nations and their power because our ancestors said so & taught us so.
I have read sapiens book 4-5 years ago and I think I had never wondered about such things until now.
Our ancestors could change things way more radically. They had such freedom.
Voltaire used his reason to pursuade people for a revolution.
I am not sure, but in the vastness of the internet, people have just stopped caring about reason but rather all they care about is authority. Change fears so many people.
People would know that some things are bad yet just because they exist, they think it as something so highly and won't even conceive of the possibility of fixing it. And others would be peer pressured into we can't change it. And the people who want change would be ridiculed and made fun of. So much of the time, reason falls off on dead ears in today's world & emotions are hijacked by echo chambers.
Much of our society(I can't say nobody,because I would do grave injustice to people who reason) wants to reason because we want the comfort of emotion.
The thing is we've only been around a tiny period of time, and given the size of the universe, it would have to be an amazingly tiny Goldilocks zone in time to actually notice us, let alone do anything about it.
Conversely, it should mean there would also be lots of civilisations millions of years technologically behind us. We're more likely to be an average civilisation than the least-developed
Apart from the Sun, the nearest star to us is four light-years away. I'm not loosing my sleep on the thought of being "discovered" by anyone over there.
But if there was a Kardashev type III civilization in the Milky Way, they would have had full control of our entire galaxy in a mere 200 million years or so. And we can be pretty sure that such a civilization doesn't actually exist. Which suggests that either advanced life is rare, or dies off long before it ever reaches such technological breadth.
Or this is merely sci-fi and it's physically impossible to build anything even close to such structures as Dyson spheres. There is no reason whatsoever to believe that just because we can conceive of something like that, it's actually possible to build it using real materials in real quantities with real amounts of available energy in a star system, and even less so to maintain these magical devices even if built.
Considering the distances between stars, we might not see civilization spreading as coherent empires but more like humans spreading through the islands of the pacific archipelago. Certainly the same species but also culturally seperated to develop on their own.
Unless faster than light travel or communication becomes avaliable, it might not even make sense to travel through the galaxy.
Maybe there's some truth to Douglas Adams' writing - we are just insignificant enough that nobody cares. In the Star Trek series it's similar, they are interested to see how pre-warp civilisations develop, seeing them as quaint, but that's it.
> Far out in the uncharted backwaters of the unfashionable end of the western spiral arm of the Galaxy lies a small unregarded yellow sun. Orbiting this at a distance of roughly ninety-two million miles is an utterly insignificant little blue green planet whose ape-descended life forms are so amazingly primitive that they still think digital watches are a pretty neat idea.
The dark forest theory makes for a great book premise, but it probably doesn't apply in real life simply because the distances are so far.
The universe is not a forest. It's a gigantic, empty ocean. The next, dangerous tribe is not lurking behind a bush 2 meters away, but is sitting on an island that's so far away it will take centuries to go there, if it is possible at all
Isn't that the point of the dark forest theory? It's not the fact that there is a dangerous tribe behind a bush it's more that you don't know if they're dangerous or not so you have to err on the side of caution - because you don't know if they're doing the same.
It's the whole chain of suspicion theory that it's safer to shoot first and then ask questions later because the speed you can communicate is the same speed you can mount an attack.
Yes, but the next bush is dozens of light years away. The analogy breaks down because the distances are different in quality.
The only reason why this becomes such a problem in the Three-Body-Problem is the existence of magic in that universe. Thinking protons, instant communication, folded dimensions, easy interstellar travel, it's all interesting speculation inspired by physics, but incompatible with our actual universe.
How do you know it's incompatible with the actual universe instead of our current understanding of the universe?
Take us for example, we're communicating instantly (for practical purposes) using thinking machines - how would that not seem like magic to someone thousands of years ago?
My point is, we don't know what the tribe have behind the bush. It's the equivalent of the Mayans wondering what's over that hill and then finding the Spanish with gunpowder, horses, and steel armour.
The only reason why we can't out sentient protons folded out of 28 microdimensions into our 3 macrodimensions is the same reason we can't rule out that our universe is actually the works of a giant hand puppet player called Zquaarx.
The problem is just - if any of what happens in 3BP was to actually happen, we would not have to be a little wrong (like Newton was in regard to celestial mechanics) but so wrong that it doesn't even make sense to apply what we know at all.
This is, by the way, the exact point of the first part of the first book: physicists discover that all off the known physics are completely wrong.
Why does the distance change the dynamic? So what if the species trying to exterminate you are 500 light years away, you think they should ignore it ?
Maximum travel speed of an extermination weapon in 100,000 years of of science may very much be impressive or even magical by today’s standards
The distance completely changes the dynamic. If I tell you there's a crazy axe murderer in your house, you should be afraid. If I tell you there's a crazy axe murderer on Venus, how afraid are you?
And unless we are completely wrong about physics, the maximum speed of a weapon will be the same as it today - very close to 1c.
Time does not matter. Space-faring civilizations can adapt their pace of life to the communication and exploration speeds or even live at multiple speeds. They are likely energy and resource-bound: within the same theory Dyson sphere is a risk, so they can only consume a fraction of locally available energy to remain unnoticed - meaning that it’s not the distance but energy consumption that will limit them.
And the evidence of that is what? What is the mechanism behind that? How is it testable?
This is what annoys me about this field. It is just magical thinking and baseless speculation. Random ideas get given names like "dark forest theory" like they are deep and consequential.
What you said is the only consequence of that "theory", because that "theory" is literally just the idle speculation that "alien civilizations may stay undetectable by hiding biological signatures of their worlds."
It’s game theory, mathematics. Let’s say every player has 3 actions: do nothing, expose yourself and destroy the player you aware about. Your goal is survival. If you expose yourself in this game and there’s at least one player choosing „destroy“ action, you loose.
Now, of course there’s a question of applicability of this model:
1. are there other players? (if the game started, we won’t know until we observe destruction event - but that’s falsifiability)
2. do they have means to destroy you? (we may find out)
3. do they have motivation to destroy you? (we may find out)
4. can you protect yourself against unknown level of technology? (we may find out).
This theory meets scientific criteria, it’s just that those criteria require level of technology that we may not reach in thousands of years.
Dark forest theory is wrong. Staying undetectable is always inferior to both staying undetectable and safely deploying varyingly detectable decoy targets at safe distance to probe the situation and gather intelligence.
Deploying decoy target requires more advanced technology (space travel) than hiding the signature (we may be able to do it long before we reach another star). I don’t think this is a good argument. Let’s say, some civilization decides to invest in decoy. It needs to shine brightly, the energy footprint is huge, a lot of work has to be done to transform the entire system. Then what? If there’s a hostile player, capable of destruction, they research and destroy the target, and start surveying the neighborhood. You cannot just build a decoy on another end of the galaxy, right? The further you have it, the more complicated is the task. And then you can only hope that the time left will be enough to collect enough energy (even if you have the tech) for defense.
Dark forest theory is about very advanced civilisations not engaging with anything around them. Limited resources are not an issue in this case. You can easily just do everything in parallel with AI or other automated control system, using stars as energy sources, including spawning whole decoy civilisations at different stages of development. Because we see so many stars we know nobody is running out of energy yet.
Possibly a more advanced civilization than us has long understood that it should not try to contact and bother other ones, but rather focus on their happiness where they are
There is no way civilizations make it past a certain point. It’s so completely obvious, just look at our world. In 2025 we are enabling a genocide while the masses don’t seem to care or even know about it.
You think the people that are having these types of atrocities committed against them would think twice about ending civilization as revenge if given the power? What do you think is going to happen with AI?
If we can’t stop a genocide, why would you think we can stop civilization ending?
>It means that civilizations should exist that are millions of years more technologically advanced than us; and should be leaving telltale signatures across the sky that we'd likely have detected by now.
Or they've reached their technological plateau millions of years ago. Like we did 50 years ago.
>And the absence of those signs would be relatively strong evidence that life, while common, isn't long-lived.
We know for a fact that life have existed on Earth for >2 billion years.
None of those discoveries help with space travel whatsoever. Our most advanced space propulsion still works on the principle of throwing a lump of matter in the opposite direction. The rocket equation remains undefeated. Special relativity remains undefeated. This is the plateau that I'm talking about. And we have zero idea if anything can be done about it.
Not sure how bad it could be given the hypothetical "millions of years more technologically advanced". They'd need to have a pretty good reason to care about us. Otherwise, we'd be so insignificant that it seems much more likely that whatever natural resources they'd want, would also be likely nearer and easier to obtain.
War-mongering, and otherwise zero-sum mentality shouldn't make all sense if they have the technology to actually reach us. [3-body spoiler warning] Kinda like in the Three Body Problem. It was kinda silly how advanced the Trisolarian were, while still bothering traveling to earth, rather than approach the problem in any number of more obvious ways
in the book they couldn't stay in their system since it was unstable and our star was the closest to them and they knew we were less advanced than them.
My prior is that life is not uncommon in the universe, multicellular eukaryotic type life less common and intelligent (whatever that means) life less common still.
If the closest prokaryotic type life is 100 light year away then the the closest intelligent life might is pretty far away.
I base this on almost nothing - other then the time it took for prokaryotic and eukaryotic life to emerge on Earth; which to my mind is surprisingly quick for the former an weirdly long for the later.
> It just seems so unlikely that we are somehow that special.
Our ability to think about those matters is conditional on emergence of intelligent life. That is our observation of ourselves is compatible with any probability of emergence of intelligent life (including almost never that is p=0).
> It just seems so unlikely that we are somehow that special.
That prior is formed by sci-fi media, not science.
> I always felt it overwhelmingly likely that it developed elsewhere too
"Life" is an information complexity characteristic. We know that information complexity is not uniformly distributed in the universe, and in fact the vast majority of the universe is extremely information-poor. Logically from the scientific data you'd assume that "life" in the universe also has a very lopsided distribution.
I never got this. Someone eventually wins the lottery. Someone eventually gets struck by lightning. How lucky a lucky person feels doesn’t influence the cold hard probabilities. So this feeling is mostly a delusion.
And frankly we don’t know how probable or improbable it is for life to form because we aren’t actually clear how it formed in the first place. The fact that the event has not and can’t (so far) be reproduced by us means that it is already highly likely to an extremely low probability event.
The question is how low? Low enough such that there is another planet that has it within 124 light years. I actually don’t think so.
I think the probability of finding a planet that has biosignatures of life but doesn’t have any life at all is a higher probability then actually finding planets that actually have life. No matter what you think the likelihood of finding life is, I think most people agree that the above should be true.
Interestingly we can’t actually know that we are correct in our calculations of what a planet lightyears away has as its atmosphere because we will never be able to go there and make sure we are correct. It’s a calculation and nothing more. For all we know that planet may not even exist. That’s what’s mind blowing about astronomy. We really don’t have any way of proving anything about what we are observing. All we can say is we are observing. That’s the only thing science can offer us.
- DMS is a very specific configuration that’s rarely the endpoint of non-living chemical cycles.
- The simplicity of DMS doesn’t make it less indicative of life—it actually makes it a very selective molecule, which only shows up in large quantities when life is involved (at least in Earth-like chemistry).
- Until we find a compelling abiotic pathway, high DMS remains a strong biosignature, especially in the context of a planet with a potential ocean and mild temperatures
Possible origins:
We’re looking at some form of life that can:
- Thrive in a hydrogen-rich atmosphere
- Possibly live in or on top of a global ocean
- Generate large amounts of DMS—potentially thousands of times more than Earth
The closest Earth analogy is:
- Marine phytoplankton, particularly species like Emiliania huxleyi, produce DMS as a byproduct of breaking down DMSP, a molecule they use to regulate osmotic pressure and protect against oxidative stress.
- If something similar is happening on K2-18 b, we’d be talking about an ocean teeming with such microbes—perhaps far denser than Earth’s oceans.
Possibly "Giant photosynthetic mats" or sulfuric "algae"
If there’s some landmass or floating structures, maybe the DMS producers are:
- Photosynthetic, sulfur-metabolizing analogues to cyanobacteria
- Living in dense floating colonies or mats like microbial reefs
- Using dimethylated sulfur compounds in their metabolism, and leaking DMS as waste or signaling molecules
===========
Of course there have been lots of ocean planets in sci-fi literature, but I'm most reminded of the "Pattern Juggler" Planet Ararat from Alastair Reynolds' "Revelation Space" series.
> Of course there have been lots of ocean planets in sci-fi literature, but I'm most reminded of the "Pattern Juggler" Planet Ararat from Alastair Reynolds' "Revelation Space" series.
Erk. Couldn't you pick something from a less... apocalyptic universe? :)
And the interstellar medium....
"On the abiotic origin of dimethyl sulfide: discovery of DMS in the Interstellar Medium" - https://arxiv.org/abs/2501.08892
"...Although the chemistry of DMS beyond Earth is yet to be fully disclosed, this discovery provides conclusive observational evidence on its efficient abiotic production in the interstellar medium, casting doubts about using DMS as a reliable biomarker in exoplanet science..."
This planet is 2.6x larger than Earth and has concentrations of DMS "thousands of times stronger than the levels on Earth".
It would take a lot of cometary impacts to seed the entire ocean with that much.
From the paper [1]:
> Therefore, sustaining DMS and/or DMDS at over 10–1000 ppm concentrations in a steady state in the atmosphere of K2-18 b would be implausible without a significant biogenic flux. Moreover, the abiotic photochemical production of DMS in the above experiments requires an even greater abundance of
H2S as the ultimate source of sulfur—a molecule that we do not
detect
And it isn’t actually signs of life. The first paragraph:
> Astronomers say they've found "the most promising signs yet" of chemicals on a planet beyond our Solar System that could indicate the presence of life on its surface.
Calling it simply an engineering issue is not properly conveying the ridiculousness of such a journey. For a small space ship of 1000 tons, this would take ten thousand times the current yearly energy consumption of mankind. So we'd need to figure out how to generate the energy and then store it on a space ship before even thinking about the engineering.
And that's ignoring the mass of the fuel. The classical rocket equation has the mass going exponentially with the velocity, which makes this endeavor even more mind bogglingly ridiculous. We'd actually need 2 million years worth of our current yearly energy consumption.
It's fun to think about, but being clear about the challenges puts quite the damper on it.
Seriously, most if not all of humanity's issue is our current energy wall. I truly wish we can invest more in energy as compared to AI because I truly believe that most AI agents are roughly the same and now are benchmark maxxing and even google's gemini is really really cool. Maybe now training it even further has less reward for the cost?
I truly wish energy could be a solved issue. I think clean energy can be great of two types, solar and nuclear, though nuclear can require a lot of expertise to build it once and operation costs, (I am not talking about the risk of nuclear reactor exploding since its just a fraction of current risks)
I personally prefer solar as its way more flexible though I am okay with nuclear as well
Mainly the issue in solar is of battery, if I understand it correctly. So We just need to really focus as a civilization to the humble battery.
My computation assumed an antimatter engine. Any drive is bound by conservation of energy and momentum.
I guess you wanted to object to an propulsion drive. Sure, you can do some fly by maneuvers or use earth bound laser propulsion, but I'm not convinced that it will put a dent in it for a regular space ship.
Also, the starshot concept won't help you with slowing down. I was assuming you actually wanted to exit the spaceship upon arrival.
Our energy production grows exponentially. For a type I civilisation, producing that kind of energy would be possible. For a type II it would be trivial. In any case the timescales involved are measured in centuries.
That's mainly because our population roughly grew exponentially lately. That won't continue.
Energy production is not something self-amplifying like a population of rabbits, so there is no fundamental reason why energy production per capita should grow indefinitely.
But sure, how you would turn sunshine into antimatter at astronomical rates might be an interesting problem to think about. But my original point that basically dismissing this as an engineering issue is a bit dishonest still stands.
If you can somehow make a ship capable of constant acceleration at 1G, and had enough shielding on it to protect it against the radiation, you can travel to any point in the observable universe, in a human lifetime.
If you just keep accelerating and left as a 20 year old, you'd be in your 50s when you saw the final stars born and die in 100 trillion (earth) years time.
If you find that sort of thing interesting... I don't always know how seriously to take the things on this channel, but I discovered Fraser Cain not so long ago and find the ideas mentioned in the interviews to be fascinating, for example "Interstellar Travel Without Breaking Physics with Andrew Higgins" https://www.youtube.com/watch?v=SkGRVvA23qI (warning: it's over an hour)
JSWT... again the most formidable piece of equipment ever shot into outer space. That think is going to shake our understanding of the Universe to its foundations a couple times around
Last time bio signatures where found (I believe on Venus), there was a flurry of papers on arXiv a week later, which all explained the signature by abiotic processes. Of course, if you have more than one explanation, then you really don't have one explanation. So I fully expect the same thing to happen here, and perhaps sometime in a decade or so follow up observations will have ruled out all but one explanation, until then exciting but ultimately it's not over before the fat lady sings.
It would be somewhat worrisome to actually find signs of primitive extraterrestrial life because of the Fermi Paradox. Given the age of the universe, and how long it took both complex life to develop on earth and for a creature such as us to emerge from that, finding life elsewhere would beg a return to Fermi's question of "Where is everyone?" implying that something comes along and causes evolving civilizations to be exterminated before they ever show signs to their presence to the wider galaxy.
If life, even of a very primitive sort, were found, it would stand to reason that it had done so in the past and that other civilizations, possibly even many of them, had formed in our huge galaxy long ago, giving them time to develop enough to be detectable even to us, so then, where are they?
Then again of course, there are probably many, many known unknowns and unknown unknowns lurking amidst all of the above supposition.
Unfortunately we cannot answer fundamental questions about ET life. Like, how long an advanced civilization lasts, which is capable of manipulating radio signals. Because we can since the last 100 years and we don't know how long we will be able.
If that time is a few hundred years, then very few happen to be functioning _now_ (in relativistic meaning) and very far away to have meaningful contact.
Here's to hoping we can learn more about this. But I feel like this could be caused by us simply not understanding how dimethyl sulfide can be formed on other planets, especially ones over 100 lightyears away..
Maybe we need to widen our search for life. Earth is a planet with about 15 degree average temperature and abundant water and oxygen. So that's what live here consumes and where it thrives. But life is all about adaptation. So, father than looking for planets with similar temperatures and resources, shouldn't we be looking for other possible foundations for life? Maybe there's a thriving civilization out there, living happily at 300 degrees, breathing neon and eating sulfur?
Is there a source for this that isn't plastered with banner ads? I can't read more than a sentence at a time without having to scroll past adverts.
I do wonder why I was stupid enough to pay for a phone with a bigger screen as it just seems to mean more and bigger ads on screen at once and the same amount of content.
Atmosphere of this exoplaned is rich in hydrogen. Also it has likely different atmospheric pressure than we have on Earth. Doubtful there is any life form as we know it. I suspect best we can expect there is something like a primordial soup: a mix of relatively simple organic compounds.
Aren't we looking into the past when looking at things this far away? So, just assuming here, that these are indeed signs of life, would that mean that "they" might have been primitive when these signatures were sent out into space and are now further developed?
My understanding is that the great filter theory means this is bad news for us humans here on earth. And considering the state of the world right now, it's especially ominous. Fate loves irony.
Not necessarily. I think it's reasonable to imagine that 'some sort of low-level life' might be fairly common across the galaxy ('one in a ten million'), whereas complex life - never mind 'intelligent' or technologically-sophisticated life might be very much rarer.
The older I get and the more I appreciate Just How Lucky we are to exist at all on our planet here, the more I favour the above thinking.
With due respect, the Great Filter is a hypothesis, not a theory.
That being said, I agree. I read in a similar thread yesterday someone confused how this would be bad news rather than good news—that there are many other intelligent species indicates that such a filter either doesn't exist or is very easy to pass. But, like your point does, I think it's important to recognize that such a "good news" position is predicated on the notion that we as a species are already past the Great Filter, rather than that we're still behind it and the others are ahead.
The great filter is only one of the possible explanations of the Fermi paradox however. There are other far less bleack including that there is actually no paradox at all: life is indeed frequent and but we are just bad at detecting it/have not been looking for it long enough.
I used to think that rare earth/rare life was the bleak option. As I get older, I think the bleak thing would be a galaxy full of technologically advanced species with morals potentially equal to, or worse than ours.
How so? If great filters exist at all, which is not a given, there could be multiple ones, first of all. They could be somewhere between our level of biological complexity and the kind hypothesised to be responsible for this signal. Endosymbiosis is a very plausible such filter. The evolution of language and the bootstrapping of cultural evolution is another one. Both n=1 on our planet. Probably there are others I can't think of right now.
K2-18 is a red dwarf. These stars often emit powerful flares that can "sterilise" lifeforms on nearby planets. Maybe microbial forms can protect themselves though?
Directly imaging an exoplanet has been done about 20 times (maybe more, by now). If you're asking how far are we from resolving an exoplanet to more than a single point of light, the answer is we will never be able to do that from this distance.
Depends on what you mean by "image". We might be able to capture blurry blobs with our current telescopes. Let's say you want to take a picture of Alien Manhattan 100 light years away, where you can see e.g. bridges and buildings, stuff about 10m across. I think we could do it pretty well if we could launch around 50,000 space telescopes, each 30 km across.
My math is below.
Note: I'm not an astronomer.
----
The angular resolution limit for a telescope is roughly the wavelength of the light it's sensitive to over the diameter.
If we want to sense things 10m across, with light at the shorter end of the visible spectrum (400 nm), we'd need a telescope with a diameter of about 1/4th of an AU (i.e. the distance from the earth to the sun), around 40 million kilometers.
More practically we could use a telescope array with this diameter, which could conveniently be in lot of orbits about 1 AU out. But the area is still a problem: assuming this 100m^2 object is as bright as it would be on earth under midday sun, it's going to be reflecting around 100 kw of energy. One of these photons has an energy of around 3 eV, so we're getting 2e23 of them a second. Unfortunately these spread out over a sphere with a surface area of 1e31 km^2 by the time they reach earth, meaning we see one every second if we have a telescope array with an area of 50 million square km.
Ok, so let's go kind of sci-fi and say we can build a 30 km diameter space telescope. It would be impressive (and unprecedented) but since it's floating in space and could be made of thin material you might be able to imagine it with today's technology and a lot of coordination. That gets us around 1000 square km! Now we just do it 50,000 more times.
Great, now we have 1 Hz of photons coming from each 100 m^2 patch of Alien Manhattan! I'm sure in the process of building 50k mega-projects we'll figure out a way to filter out the noise, and with a few years of integration we'll have a nice snapshot!
This is very exciting. It's certainly approaching the best evidence we could possibly hope for from an exoplanet given current technology.
Of course, the weak link here is the assumption that these bio-markers can't be produced abiotically, which is a pretty big assumption. Our understanding of planetary science is still in its infancy. This is (thought to be) a hycean planet, a type of planet unknown to us until very recently(post-JWST, I believe?). And given that the solar system has no hycean planets, it's a class of planets which is fundamentally poorly studied, with pretty limited access to data. We can make models, and we can get some spectral data on the contents of their gaseous atmospheres. But we have no way of looking at their surface oceans. Thinking about what kind of chemistry might be going on there is mostly just an act of speculative modelling.
So the interesting question is, without new sources of data, can we determine whether these bio-markers are biological in origin? Not really. Not without a much better understanding of planetary science in general and hycean worlds in particular(of course, that's what this research is trying to do, and making progress at). As well as a deeper understanding of abiogenesis. I could imagine a working understanding of abiogenesis at least being able to eliminate some candidate planets, but even that assumes only one type of abiogenesis is possible, which is more or less unfounded. That is, unless the understanding includes some deep information theoretic/evolutionary perspective on abiogenesis which would probably have to include a completely unambiguous information theoretic and physical definition of what life even is. It is conceivable that such an understanding might provide very strong restrictions on what kinds of chemical systems are capable of abiogenesis, and that those restrictions could then be used to eliminate certain planets or even entire star systems from contention. And if these hycean worlds were eliminated that way, we'd know there must be some abiotic source of these "biomarkers", and knowing that, we would likely be able to figure out what it is. But ok, that's a lot of assumptions.
Maybe we get lucky, and some chemists stumble on a non-biotic chemical system that can produce these chmicals in concentrations that can be detected by JWST at a distance of hundreds of light years. Or, conversely, maybe chemists somehow manage to prove conclusively that biotic origin is the only possible source. I'm not a chemist or a microbiologist, so I have no idea what that would look like. It's probably well beyond our current understanding.
I guess what I'm rantingly saying is, while this result changes my credence that there's life on this planet about as much as is possible with current science and technology, it still barely changes it at all. Before it was maybe 0.5 + ε(habitable zone, liquid water), and it is now 0.5 + 2ε.
I guess something which could move the needle much more significantly, is if we found a large number(say 10) of chemically unrelated potential bio-markers in the atmosphere of a planet very similar to earth, in a very similar star system. Then, the assumption of the impossibility of abiotic sources would be much more plausible. I believe doing this type of research for earth-sized exoplanets with JWST is still quite borderline(please correct me if I'm wrong).
Having said all that, this result is still extremely exciting. For the first time, the field of exobiology has any contact with observational data from outside our solar system at all(besides mere astronomical data), and things will only improve from here. Future telescopes will be better at this type of observation, and our understanding of planetary science is evolving at an accelerating pace. I'm very excited to see where this research goes in the future.
This is a terrible title. The original title was:
"Astronomers have found the 'most promising signs yet' of alien life on a planet beyond our Solar System"
"Astronomers have found signs of alien life on a planet beyond our Solar System" means something completely different. Please @dang update or this looks like the Daily Mail.
It's an example of scientists acting irresponsibly. They might have found dimethyl sulfide but it can be produced abiotically.
The planet looks more like a Neptune or Uranus than Earth type. They need to find multiple examples of different types of biomarkers, before contacting the press as they obviously did.
Housing prices have almost nothing to do with space programs. In most places, they’re an artifact of laws and policies which create scarcity for the benefit of rich property owners, and cutting scientific research entirely won’t change that except in a few cases where you’d be able to bid on a house which some unemployed scientist or engineer is forced out of - but the private equity guys will probably outbid you.
There was this post on HN that life can't be given to mars for 99.99% and even if it could, it would be the most miserable life with only 1-2 decades. It isn't self sustainable as people imagine it to be.
So all we have is, is this Earth & our fellow human beings & instead of treating each other with basic necessities like housing, education , healthcare.
Also these things, in my opinion of researching the space and giving housing, they aren't mutual. They can both be done but even if they are mutual,I would personally pick housing any day, because what point is of space, what point is of going to outer space some day and living shit there if humans are currently living shit here as well.
Regarding Housing, I think it can easily be fixed and so much more like how we say tax the rich, if we could just tax lands.
Because people think of land as some "asset" and that they "own it" ,when in actuality, I might argue that land is the only thing that I personally think the govt. has any right over. So I personally believe that we are better off taxing land so that these pesty landlords who get rich off of the housing crisis can really just suffer so much that the lands would just be productive and not speculative , reducing the price of lands down and even rents down till the point housing is way more favourable.
Its a net win to everybody except those pesty landlords & maybe "investors" or people who bought housing pre-georgism because they might now believe that its unfair to them?
Still I think that georgism is pretty flexible and this could be sorted out in such a way that it would have been less controversial and more net positive to the Society than the latest tariffs fiasco, though people didn't vote for housing, they voted for tariffs.
To be fair, there’s a big difference between journalists and headline writers!
Headline writing is the art of taking something that a journalist has thought about in detail and carefully crafted and making it into something that someone with low to zero interest in the topic might want to read.
Having done both, I got annoyed when headlines misrepresented what I’d written, and journalists got annoyed when I took their perfectly crafted but pedestrian articles and gave them punchy headlines in a desperate attempt to get people to read them...
Fair enough! Also, to the credit of headline writers, I have sometimes clicked on a clickbait article and learned something. If it hadn't been clickbait, I might have missed it.
- detected dimethyl sulfide and dimethyl disulfide, false positive possibility is now very low
- "produced by marine-dwelling organisms on Earth", possibility they were produced by other processes (unrelated to life as we know it) not high but maybe unknown unknowns
- other factors like distance from the star are in favor of life & water
- previous studies detected methane and carbon dioxide
It's not that low, unfortunately. From the article:
> They say their observations have reached the ‘three-sigma’ level of statistical significance. This means there's a 0.3% probability the detection occurred by chance. And to reach the accepted level that would mean scientific discovery, observations would have to meet the five-sigma threshold. In other words, there would need to be below a 0.00006% probability they occurred by chance.
Thats what I'd like to know, is this the kind of process that we can _get_ to 6 sigma by more observation time? Or would we need other observations / thats "as good as it gets" for the Webb's capabilities?
> The observations also provided a tentative hint of dimethyl sulfide (DMS), a possible biosignature gas, but the inference was of low statistical significance.
From the source paper. It is a very important result but not definitive, false positive is still possible as well as us finding a new way in which DMS can form without a biological process.
Still freaking exciting and fantastic scientific achievement. JWST is already bearing incredible fruits.
Suppose it were somehow possible to prove that alien life exists. Like, we get a radio signal saying "hey, Earth! We see you looking at us!" that's conclusive and undeniable.
That would upend a lot of religious teachings which say we're unique and that the world was given to us, as the unique creations of a creator, to consume for our own benefit.
It seems like there could be many practical benefits to showing that's not true. Hey, maybe the concept of infinite exponential growth is a bad idea. Maybe we shouldn't burn the skies and boil the seas. Maybe we should be nice to other intelligent animals, at the very least.
Beethoven’s music directly impacts human lives. It evokes emotion and inspires creativity. Its value lies in its immediate effect. In contrast, knowing that life exists millions of light-years away offers no such tangible impact. It’s a data point. An interesting one, sure, but it doesn’t feed the hungry, cure disease, change policy, or even affect your commute. So yea, Beethoven is a lived experience, whereas aliens in Andromeda are an abstract concept.
If you wake up tomorrow still alive, you can visit HN and downvote my comments. That will impact my karma value. Not a big deal, but still. If there is alien life, you can’t do anything about it. Zero impact.
124 light years seems quite close, it seems to be some sort phytoplankton for now, what can we send there quickly to eradicate them before they become a problem. How much mass of galactic "roundup" should we send ? Do we have the technology yet for planet-scale sanitizing ? Can we pulse some high energy particles at roughly the speed of light and aim it at them ? Do we know if they have some magnetic field protection like earth does ?
Here's the primary source
https://iopscience.iop.org/article/10.3847/2041-8213/adc1c8
They possibly detected dimethyl sulfide, which is only known to be produced by living organisms.
A lot of science papers are like “we found a hint of this thing, we need to do more research” and it’s reported as “ALIENS??!?”
I understand why this is the case but I think it can lead to a loss in trust in science when the reporting jumps to conclusions that aren’t supported by the research itself.
In this case the abstract is far more grounded. In particular,
> The observations also provided a tentative hint of dimethyl sulfide (DMS), a possible biosignature gas, but the inference was of low statistical significance.
> We find that the spectrum cannot be explained by most molecules predicted for K2-18 b, with the exception of DMS and dimethyl disulfide (DMDS), also a potential biosignature gas.
> More observations are needed to increase the robustness of the findings and resolve the degeneracy between DMS and DMDS. The results also highlight the need for additional experimental and theoretical work to determine accurate cross sections of important biosignature gases and identify potential abiotic sources.
I think you have misread the abstract. The 'low statistical significance' was a [prior work](https://iopscience.iop.org/article/10.3847/2041-8213/acf577). This paper has increased the significance to 3-sigmas which is on the lower end but still quite significant.
Yes you’re right, thanks.
Ugh, "alien life" is a reasonable title, IMO. I think the sensationalism is happening in your head, that you're imagining the Borg or little green men.
I don’t think it’s an unreasonable title, but it’s also not accurate. The paper states quite clearly that they’ve found reasonable evidence of a known biomarker. They don’t know enough to say whether it’s from a biological or some abiotic process (but speculate a little about what that might mean and what evidence they would need to take that further).
That’s quite a different tone from the article, and I think the comments here and elsewhere online reflect that.
More like big green algae?
I'm imagining some new kind of volcanism and one less way to detect life. Or, as my wife put it, "Ah, rock babies again."
The scientists are also saying ALIENS! but they're covering their backs, they want their research to make headlines too
I'm not convinced about the methods. It looks a lot like p-hacking to me: they have a highly specific hypothesis drawn from a large universe—that dozen or so molecules (§3.1) in their infrared spectrum model they're fitting experimental data against. I don't buy the way they created that hypothesis. The put a handful of highly specific biosignature gases into it, things that were proposed by exobiology theory papers. One very specific hypothesis out of many, and a low likelihood one. And that's the hypothesis they get some borderline ~3σ signals for? Really?
edit: Any chance someone might have the charity to explain why my criticism is so far off-base, according to the HN consensus?
I'm going to double-down on my stubborn, unpopular opinion. This is my best attempt at explaining my criticism:
- Alien metabolites are a low-prior probability hypothesis. Dimethyl sulfide is a long-postulated biosignature with no natural source, so, it's low-prior
- The paper's model fits Webb data—a handful of photons—against no more than 20 candidate molecules, combined across all of their atmospheric models. Many of those gases are drawn from that low-prior "alien metabolite" class
- There's a much larger class of strongly infrared-absorbing gases, that can naturally occur in planetary atmospheres. Beyond those included in the 20 candidates. These (should!) have higher prior probability of occurring in Webb data than alien metabolites. (This class is so large and complicated, there's major spectral features in our own solar system's gas planets we haven't characterized yet)
- If you were to fit Webb data against that expanded class, those alternative hypotheses, you'd get a large number of 3-sigma detections by pure chance.
- The Webb data is too weak to distinguish between these. With only a few bits of information, you can distinguish between only a small set of alternative hypotheses
- This paper elevates the alien-metabolite hypothesis very highly, and that is why when it has a spurious statistical detection, it happens to be an alien metabolite detection. Because that hypothesis is overrepresented in their model
- The root problem is that since there's only a trickle of real data from this exoplanet, from Webb, it's unlikely one can infer anything super interesting from those few bits
False positives are acceptable if the goal is to generate leads to follow up on. If the detection was due to chance then it won't hold up to further measurement. There's few enough hits that we don't need to worry about being more rigorous (and potentially introducing false negatives) at an earlier stage.
Given the context, a publication seems appropriate. A high profile similar example is when neutrinos supposedly broke the light speed barrier. If the mass media misrepresents things that's hardly the fault of the scientists.
So if I understand correctly, this[1] is what they did?
[1] https://xkcd.com/882/
Don't be bothered by the down votes. HN consensus is not something worth pursuing. Your criticism is valid, it's just that it runs against what HN readers want to believe in this instance. Readers here like to think they're motivated by reason and intelligence and whatnot, but that is laughable - examples of logical fallacies and assertions of fact rocketing to the top comments abound. Overconfidence and readiness to accept bold claims is a more dangerous cultural dysfunction than the lack of seriousness and ubiquitous monetization that plagues other platforms.
In any case this study will likely go on the pile of papers judged by time to be an overreach of conclusions and a dead end.
also: https://arxiv.org/abs/2504.12267
(if you want a cleaner interface)
only know to be produced.....is a whoa bessy phrase,?¿ as in 70 years ago an undergraduate figured out that dimethyl sulfide was produced by living organisms and he asked his professor what else made it, and got shrug and "nothing else I know of" and everybody has been cutting and pasting since, OR, an international team spent years and millions working on the chemistry behind dimethyl sufide in an epic known to all quest to determine it's origins. Science does have an issue with cutting and pasting ancient mistakes, and then bieng exceptionaly reluctant to change and move forward, not to mention that SETI, and the rest of "alien" research is most definitly tainted with public fantasy and entertainment industry influence, so even with one of the notoriously oderiferous sulfide compounds present, I wont hold my breath
Ya, it’s a bit less exciting, but I bet we’re about to learn many new ways to produce dimethyl sulfide outside of a living organism
actually we know how to produce it without involving living organism
https://en.wikipedia.org/wiki/Dimethyl_sulfide#Industrial_pr...
actually a living organism is needed to produce it this way
Wikipedia says "In industry dimethyl sulfide is produced by treating hydrogen sulfide with excess methanol over an aluminium oxide catalyst”.
Which part requires a living organism?
I think they are being a little glib by saying a human is need to make the industrial processes.
Well, someone needs to treat the hydrogen sulphide with excess methanol over an aluminium oxide catalyst. I suppose a robot could do it...
For a non-life explanation, you're really looking for something that could plausibly happen in (abiotic) nature, not an industrial process.
The only thing that could make a nerd happier than detecting alien life would be detecting alien robots.
Wait, what's the difference?
Alien life could just be microbial, while alien robots would require an advanced technological civilization, I guess
Well, there could be nanobots...
Virtually all of them involve non-trivial design by sentient beings.
And the question is even more complex: not whether producing dimethyl sulfide "from scratch" without involving living organisms of the familiar sort is possible (of course it is), but what the hypothesis that each of the numerous possible ways to produce dimethyl sulfide happens naturally (or that alien lifeforms want a lot of it) implies about the environment of the exoplanet.
> which is only known to be produced by living organisms.
Comets with DMS: https://arxiv.org/abs/2410.08724
And the interstellar medium.
"On the abiotic origin of dimethyl sulfide: discovery of DMS in the Interstellar Medium" - https://arxiv.org/abs/2501.08892
"...Although the chemistry of DMS beyond Earth is yet to be fully disclosed, this discovery provides conclusive observational evidence on its efficient abiotic production in the interstellar medium, casting doubts about using DMS as a reliable biomarker in exoplanet science..."
But in a concentration sufficient to be visible from this far away with spectroscopy?
It's not definitive but it is suggestive. A detection would require multiple pieces of evidence. We should be building specialized space telescopes designed specifically for the characterization of extrasolar planet atmospheres, since that's the best way we have to potentially detect something.
Thank you for posting this. Really balances out all the conjecture.
Firstly that is completely badass science. The idea that you can use observations to detect the chemical composition of an exoplanet millions of kilometres away is an absolute triumph of the work of thousands of people over hundreds of years. Really amazing and deeply humbling to me.
Secondly, my prior was always that life existed outside of earth. It just seems so unlikely that we are somehow that special. If life developed here I always felt it overwhelmingly likely that it developed elsewhere too given how incredibly unfathomably vast the universe is.
If life is very common in the universe, then that is probably bad news for us. It means that civilizations should exist that are millions of years more technologically advanced than us; and should be leaving telltale signatures across the sky that we'd likely have detected by now. And the absence of those signs would be relatively strong evidence that life, while common, isn't long-lived. Suggesting that our demise too, will come before too long.
If, on the other hand, life is relatively rare, or we're the sole example, our future can't be statistically estimated that way.
It is quite plausible that life is abundant, but sentience is not. If we take Earth, it formed 4.5 billions years ago, conditions became suitable to support life like 4B years ago and first known signs of life are dated 3.7B years ago.
Now, in just .5B years Earth would likely become uninhabitable due to Sun becoming a red giant. In other words, on Earth life spent 90% of its total available time before sentience emerged. So on one side life is constrained simply by time, and on the other, sentience might not be necessary for organisms to thrive: crocodiles are doing just fine without one for hundreds of millions of years. To think of it, it is only needed for those who can't adapt to the environment without it, so humans really might be very special, indeed.
This is now much less plausible. Intelligence, like eyesight, is believed to be a result of convergent evolution[0].
[0] https://www.quantamagazine.org/intelligence-evolved-at-least...
Being intelligent doesn't necessarily lead to runaway technological development. Dolphins are smart but they're never going to invent radios to broadcast their existence to other star systems. They're stuck in the water and don't have thumbs. And even orangutans, who have thumbs and live on land, don't seem tracked for technology even if humans weren't around; their ecological niche is small even if we assumed humans weren't wrecking their environment, and they seem comfortable and steady in it.
We don't even need to look at other species.
Humans have been just as smart as you and me, maybe even smarter according to cranial measurements, without inventing anything that significantly changed their way of life.
There could be loads of planets with prehistoric humans, having a fine time hunting with bows and picking fruit.
I think by the time we get to modern humans it would only be a matter of time for technology to develop to something like the current stage. The main evidence I can think of is the independent development of agriculture in about 4-5 regions, and the independent development of large complex civilizations in the Americas and Eurasia.
Humans are cultural learners, so this allowed cumulative cultural evolution from at least as far back as the transition from Olowan to Acheulean stone technologies with Homo erectus ~2-3 million years ago. By the time we get to Homo sapiens and Neanderthal this capacity for cultural learning seems much increased. Some paleoarchaeologists (e.g. Dietrich Stout) argue that technological development has been exponential as far back as H. erectus, just that the early stages of the exponential curve look flat for a long time.
I think it only takes a small tweak for everything to stall.
Suppose say, that people only trust a small group. Extended family and lifelong friends, for instance. People get very violent as soon as they disagree on something, immediately wanting to settle disputes by force.
Nobody can strike a deal to do anything with anyone outside their group, and you certainly can't make agreements with a guy in Seattle to deliver things to London. You can't mine coal hoping to sell it to an as yet unknown person. There's no point in fishing more fish than you and your friends can eat.
What happens in this world? Well, I think people will still be intelligent. They'll still think about social situations, especially when it comes to mating. There will still be stories, and humor.
But we're not advancing tech, and we're not changing economically.
Why do I say it's a small tweak? Well, we've all met people who seem to not be able to work with anyone. It's not unlikely that out in the stars, there's some planet with people who have everything we have, but they can't get things to work.
Mutation is random but selection is non-random. Multilevel selection could select against those scenarios you're talking about. Collaboration could be yet another thing that comes from convergent evolution.
Random walks only progress if they don't get trapped in a local minima. GP example is but one entirely contrived scenario. The point is that technological development depends on many factors and it's entirely plausible that some of them aren't strongly selected for.
This seems to be supported if you consider how long it took for humans to emerge and the fact that other fairly intelligent species exist alongside us but didn't follow the same path. If you suppose that technological development has a clear selection path then why isn't there any evidence of space fairing dinosaurs?
Humans only started planting grain about 12k years ago. Anatomically modern humans were gathering wild grain, but not planting grain, for about 100k years. Given this very long period of stagnation, I don't think humanities ascension was an inevitability.
I know about the Natufan culture gathering and processing grain with grindstones from about 20k years ago, but don't remember anything from 100k years ago. Were they using grindstones to process grain? I'd have thought grass grains wouldn't be a good food source otherwise.
In any case, the seeming stagnation is part of what I meant by the early part of an exponential curve looking flat: broadly it might look like not much is happening, but there are small changes all the time.
Lack of evidence is also a problem when looking that far back: we have little concrete evidence of what these people were doing with wood, fibres, and other perishable materials.
Having said that, archaeologists used to talk about a "cultural revolution" that happened 20-30k years ago. (Maybe they still talk about it, I just haven't looked at the research recently). This was the period of the famous Lascaux cave paintings and what looks like an explosion of greater complexity in tool assemblages. So it's possible there was some rare cognitive leap at that time, or again it could be that we lack the evidence that would show the more gradual progression.
We really are pretty lucky that the industrial revolution happened. Thank god for England running out of trees to heat homes with, and abundant surface coal on that island.
I don't think so, though. I think that unless there are limiting factors (no ores or some other necessary component) life would tend toward technology.
Curiosity as an evolutionary trait is quite an advantage, and I would think is necessary for intelligent omnivores. It's what helped us figure out what we could and couldn't eat, and taught us better techniques for living. Curiosity naturally leads to technological developments, I would argue.
All humanoids except our species are extinct, and it's not because we killed them.
It's not? Didn't most of them coexist with us until they didn't?
> life would tend toward technology
Based on what evidence? We only know if it happening once, after a very long delay.
I think it's a natural product of curiosity. And I think that intelligent life would only be so because of curiosity.
You want to figure things out or you're interested in seeing what happens when you fuck around with things.
So I think a technological progression is a natural progression for intelligent life.
Does that make sense? I feel like I'm not explaining myself well.
Lots of animals have been curious for hundreds of millions of years, but technology more advanced than breaking bits off rocks and sticks has only been around a couple thousand years. If you say it's a "natural progression", you also have to say there are serious barriers that most species will never pass.
Okay?
So the notion that "life would tend toward technology", charitably speaking, does not make any useful predictions. Based on all evidence available, including the dearth of extraterrestrial technosignatures, you can't rely on it happening in any particular situation or timeframe. At best it's speculation, more likely it's just false.
Correct, we disagree in what we think.
> Dolphins are smart but they're never going to invent radios to broadcast their existence to other star systems.
How could we possibly know this? The only case of "Dolphins" we know of, is on Earth, with the interference of humanity, and we're looking at Dolphins at a really small timescale.
Given N thousands of years without interference from other species, who can really confidently tell exactly how Dolphins would evolve?
We've had at least two developments of ""dolphins"" that I know of. We also have other intelligent sea life, like squids and octopuses, who've been around for a hell of a long time and are on track to never develop advanced tool creation and use. Living in the water is a massive tech nerf.
Notably the latter example has ideal appendages for tool manipulation - likely far superior to primates with thumbs. Yet somehow they're indefinitely stuck without tool use.
I wonder if things would progress if they had the same level of communication that dolphins do.
> Living in the water is a massive tech nerf.
Says land-living animal :)
Again, are you saying that you confidently can predict a hypothetical future where Dolphins, even given millions of years, would never invent the radio? I think it's unlikely too, but so are humans, so who knows what could happen.
Living underwater puts a dampener (didn't intend this atrocious pun, sry about that) on any technology that depends on fire. So smelting ores seems out of the question, and of course radios are made out of lots of pieces of metal.
I can't think of any plausible ways a water-bound species would be able to harness and use electricity either
Besides the whole fire thing, which is a serious problem for the metallurgy necessary to make radio, to have any chance of it they'd need to get fingers instead of the optimal swimming flippers they have now. They'll never do that as long as they're aquatic. If millions of years of evolution has them climb out of the water and become land animals again then there might be a glimmer of hope for them, but then they'd no longer be recognizable as dolphins. As it stands now, field mice have a more direct path towards becoming radio makers than dolphins do.
Nevertheless, if abiogenesis is common & intelligence is easy for evolution conditional on abiogenesis, the number of explanations for the Fermi Paradox just shrunk by a great deal, increasing the probability of the remaining explanations.
I doubt there is one single grand answer for the Fermi Paradox. Probably it's lots of smaller blockers which all stack up with each other. The chance of life forming, the chance that it becomes multicellular, the chance that it develops complex nervous systems, intelligence, the physiological hardware for tool use and creation, not stagnating or getting wiped out, having the inclination to look out and broadcast their existence, the chance that they survive long enough while doing this to exist at the same time as another civilization of comparable development, etc. It's easy to come up with these and even if they all have modestly small probabilities each, together they stack up to a plausible answer to the so called paradox.
The paradox would remain valid in my view. Even with all those stacked difficulties and plausibility levels, the galaxy alone is immense and if life of any kind were to be found, i'd argue that we should be able to see signs of sophisticated life somewhere at least, so where is it? It's still a cause for some speculation and maybe even existential worry.
The galaxy isn't really that huge. 10e11 stars. If you stack only a dozen obstacles at 10% odds of overcoming them each, you come up with advanced radio-broadcasting life being an unusual outcome for a galaxy our size. Add a few more and you can bet against another advanced civilization coinciding with us in the entire observable universe.
Dolphins have only lived in the water for 50m years or so, they still breathe air. They could re-adapt to the land in that kind of time frame easily.
They'd still be dolphins in the same way that you are still a fish.
Also, I don't think you're right that they could do this easily. Their hind limbs have almost completely vanished, their pelvis too, and they have no chance of moving on land. To have a chance they would need to redevelop those things which they've lost, and I don't think there's a particularly plausible path where each step helps their survival at that step. In contrast, their four-limbed land adapted ancestors could swim much better than dolphins can walk.
Birds are not remotely as smart as humans.
The sun has about 5B years more to go before it turns into a red giant, not 0.5B years...
According to this Timeline of the Far Future [0], we only have 500-600 million years.
(warning, this is one of the most depressive pages on Wikipedia)
[0]: https://en.wikipedia.org/wiki/Timeline_of_the_far_future
You confused two things. There is the Sun turning into red giant in 5 billion years consuming the Earth, and the Sun getting too bright for Earth to be habitable in 500 million years.
While it has more time to become a red giant, it'll become more luminous over time and life on Earth will be impossible much earlier. I've seen estimates of 0.5B to 1.5B years.
Nothing a bit of stellar lifting would not fix[1]. Or worst case, move to a bunch of habitats orbiting stellified Jupiter[2].
[1] https://en.m.wikipedia.org/wiki/Star_lifting [2] https://www.orionsarm.com/eg-article/4a48d58c84350
That's not the point: if you have capabilities to do stellar lifting, interstellar travel is likely on the table too. Fermi paradox is about the question, why we can't detect any sign of extraterrestrial civilizations out there. One explanation is that while life in general might be relatively abundant, true sentience as in us humans that allows life to spread besides its cradle might be quite unique.
In 500 million years, hopefully humans (or whatever humans have become at that point) will be able to modify the Earth's atmosphere to deal with the increased luminosity of the Sun.
We might be lucky enough to do that, but it could have easily taken intelligence another 500M years to evolve on another planet. First animal fossils are something like 700M years old, so it took 2-3G years to just any animals.
The problem is that there are just so many planets. Sure, another planet could be 500My slower, but with a billion planets, some of them should be 500My faster instead.
It's possible we are absolutely one-in-a-billion uniquely lucky - after all, someone has to be the first and the luckiest. But every year we find indications that our planet is completely typical.
Yes but the point is that the window in which we have developed this capability is quite short.
You're assuming we make it out of the industrial age while we backpedal on all of our climate commitments.
We'll put a giant sunshade in the Earth-Sun L1 Lagrange point.
We might need to do that by the end of this century.
If we are able to harvest the solar system resources it would take by then.
Trial run for the bigger “solar warming” event.
See, it all comes together! ^.^
Sadly it is still only a stop-gap measure. The sun is for all intents and purposes, dying a slow death.
We'll have colonized the galaxy in 10 million years. In 200 million years, I'd expect that some future historical society could undertake a project to clean out the heavy elements in the Sun to keep it going.
Yeah, but if humans exist by the time the sun fails us, they wouldn’t really be the same species as us, and they’d hopefully have progressed to the point that they could escape the Earth.
You're saying we wont maintain tradition and our "humanity"?. I like to be a little more optimistic and believe in us as a species transferring values until the end.
Look at all types of mammal that exist, from us to platypuses to bats to whales. Evolved in a few hundred million years. Modern humans have been here for a few hundred thousand.
In 500 million years absolutely anything could happen (if we survive this century).
Long before death it will expand to or almost to Earth's orbit. I doubt humanity could isolate Earth from that.
Sure, but it may keep Earth habitable for an extra billion years.
Unfortunately it looks like we are more in the track to human inhabitable earth :(
Sure, and entropy will end us all one way or another
lol 0.5B to 1.5B is a pretty big difference. Sounds like we really don’t know what we are talking about.
The lower end estimate depends on the specifics of the increase in brightness accelerating the weathering of silicates, leading to more CO2 absorbed out of the atmosphere until C3 photosynthesis isn't possible. Some plants use a different method which will continue to work (C4), but consequences of plant life as we know it dying off would be catastrophic for life on this planet - barring of course, whatever adaptations are made.
But it's certainly the mark of "the beginning of the end" for life on this planet - it's a major milestone that we (the species) do need to leave eventually if we want to continue.
Maybe it'll help if you think of it as 5-6.5 billion years instead.
Every field of study, subject, or problem, or even business cases, -- all have different ranges.
Why does this one in-particular sound like they don't know what they are talking about? It would be just as accurate for me to say in the range of responses, yours kind of sounds like an anti-science bot. Typical of that type of thinking.
The difference between .5B years and 1.5B (BILLION) years is pretty staggering in a conversation basically focused around the last couple thousand years. Definitely room for the comment.
Your anti-science bot comment however, is very anti-science.
Really? With the age of a star, that is too wide a range for you to accept? To pinpoint something like this. What if I were to say, "really it's 1.3435 Billion on a Tuesday".
Of course, calling someone anti-anti-science. The new 'right'. Using science arguments against science. Yes. Your comment is typical, just spam fud. "look at this huge range, see, scientist don't know what they are doing"
Earth may become uninhabitable in 1By due to increasing brightness of the sun. In 3-4B years it will be too hot for liquid water on the surface.
Earth is on course to become uninhabitable for human civilisation its current form within a century, with an associated mass extinction.
Even if all industrial activity stopped tomorrow there's now enough CO2 in the system to guarantee a succession of uncomfortable and expensive droughts, floods, storms, and wildfires for thousands of years.
If it doesn't they will become more and more extreme very quickly.
If ocean acidification and warming destroy the foodchain in the seas, collapse on land will happen very quickly.
Did you notice that you aren't wrong because you're not really saying anything at all? "in its current form" - so maybe with slightly different distribution of land use but basically fine and not necessarily as different as today is from 50 years ago? "mass extinction" already been happening for ages for many species. "uncomfortable floods/etc?" Already been happening for all of history. "very quickly" is how quicky? "more extreme" is how much more extreme?
> so maybe with slightly different distribution of land use but basically fine and not necessarily as different as today is from 50 years ago?
No, probably very much more different than that, more like rolling back on industrialisation and globalisation. Closer to 500 years than 50, without the same hope of "progress" that we had back then.
> "mass extinction" already been happening for ages for many species.
Yeah, we all learned about dinosaurs when we were little kids, but if humanity collapses there's no guarantee of anything similar developing after us.
Indeed.
Maybe once day, aliens will drop by and discover what remains of humanity. And stories will be told of how, when the time came, our species decided to bury its head in the sand and hope the problem would go away. Or maybe that we attempted to create god to come rescue us.
Life imitates art. We refused to listen to the scientists.
Why do you think aliens will drop by? If aliens were visiting every planet in the universe, don't you think we would have noticed that by now? I mean, why didn't they visit the solar system and colonize it (and everywhere else) aeons ago?
Someone has to be the first.
So, your theory is aliens are abundant, but by extreme coincidence we're first?
We haven't visited any other planets so we're not the first either.
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5B more years and we're here for max 100 years. Cruel joke. Life's too short.
You may want to update your view that non-human animals lack sentience. [1]
[1] https://pmc.ncbi.nlm.nih.gov/articles/PMC4494450/
If you're referring to technology/civilization-building capabilities, that is a different matter.
I owned quite a number of pets in my life, so I don't need explaining that they do have some kind of relatively high-order intelligence that allows them to do quite a lot of things. Yet, this is clear that no kind of animal on Earth but us exhibits potential to have capabilities to spread themeselves beyond home planet once it becomes uninhabitable. Moreover, signs show that once a type of species finds their niche, their intelligence levels off and does not tend to increase. In other words, modern crocodiles are no smarter than crocs from 10 millions of years ago, because they are doing mostly fine as they are.
Yes, I think GP phrased it badly. This is just about the meaning of words: "sentience" just means sensory or experiential consciousness. It doesn't necessarily imply high intelligence or capacity for using technology
The fact that sharks have existed for 450 million years fairly unchanged fills me with hope. Our existence might be a huge fluke even if eukaryotic life can happen once and again in the Universe.
why isnt a crocodile sentient?
Technically, it is: https://en.wiktionary.org/wiki/sentient (the first two definitions). You mean the science fiction definition though (the third), and it's because it's not self-aware and not very intelligent, because it doesn't need to be to survive and procreate successfully. A slightly smarter crocodile must not have enough of an advantage over its peers to matter for evolutionary purposes.
Honestly, I do not think high-intelligence is useful for life. The most successful life forms aren’t the most intelligent, and humans seem to be fixed to self-annihilate.
what do you consider the most successful life forms to be? humans currently inhabit every continent and are unquestionably at the top of the food chain.
Are we though? Bacteria do better than us. Cockroaches. Rats. Ants. Grasses. Plankton. We aren’t the most numerous. We aren’t the most widespread. We are serious risk of killing off our own species.
If the Earth was about to be hit by a huge asteroid, some people might survive (by fleeing in spaceships) but none of the species you list have a chance unless people choose to save them.
I highly doubt much of the bacteria would care. The amoeba probably wouldn’t either. Also, rodents have already survived such impacts. All mammals alive today are alive because our ancestors didn’t die with dinosaurs.
Suppose the asteroid is much bigger than the one that ended the dinosaurs.
If the Earth is completely destroyed, the humans on space ships wouldn’t survive either. There is no self-sustaining off world colony currently, and there most likely will not be in the lifetime of anyone alive today. At such time that there is, bacteria, rodents, and other life will likely come with humans as humans build the biospheres that we need elsewhere.
With a few years to prepare, the humans would have a chance IMHO.
Who says they aren't? Of all the reptiles, they seem among the smartest.
> in just .5B years Earth would likely become uninhabitable due to Sun becoming a red giant
The Sun will not become a red giant in 500 million years.
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You seem to be conflating life, multicellular life, and intelligent life. Life appears to have developed on Earth pretty quickly, multicellular life took a long time to appear, and we are only aware of one species that developed civilisation building capabilities.
Life might be very common, but intelligent life still be incrediblY rare.
It depends what you mean by "civilization building". I think we gloss over that a bit too much. We're not the largest population, not the largest total mass, not the only one that builds large structures. We're the only one that sent stuff outside of Earth, yes, and a few other things. But discussing the definition is itself interesting
Human civilisation means intelligence and memory are collective, externalised, persistent, communicable. There's also a layer of symbolic abstraction (science and math) which makes it possible to predict useful consequences with some precision.
Individuals die but their inventions and insights remain. Individuals can also specialise, which is a kind of civilisational divide and conquer strategy.
Most animals don't have that. Some do train their young to a limited extent, but without writing the knowledge doesn't persist. And without abstraction it only evolves extremely slowly, if at all.
They have to reinvent the wheel over and over, which means they never invent the wheel at all.
We actually have this problem with politics and relationships. We keep making the same mistakes because the humanities provide some limited memory, but there's no symbolic abstraction and prediction - just story telling, which is far less effective.
Bonus points: I often wonder if there's a level of complexity beyond our kind of intelligence, and what it might look like. Abstraction of abstraction would be meta-learning - symbolic systems that manipulate the creation and distribution of civilisational learning.
AI seems to be heading in that direction.
There may be further levels, but we can't imagine them. We could be embedded in them and we wouldn't see them for what they are.
If you include our crops and livestock then our civilisation has about half the land biomass. 38% of the earths land is farmland. (We use the richest parts as farmland) https://www.ncesc.com/geographic-faq/what-percentage-of-land...
Another 34% is Forrest, much of which is managed for logging.
We are capable of rapidly changing chemical composition of atmosphere, which may be noticeable even at our technological level.
Plenty of lifeforms have changed the composition of the atmosphere. At faster rates than we are changing it now.
The only similar example I can think of is when, roughly 2400 million years ago (during the Paleoproterozoic iirc), the ancestors of cyanobacteria poisoned their atmosphere by overproducing oxygen which resulted in an extinction event. But that whole process still took somewhere in the order of millions of years to complete I believe.
> But that whole process still took somewhere in the order of millions of years to complete I believe.
The geological evidence is that that oxygen build-up first had to exhaust things that took the reactive oxygen out of the air and water. Iron oxide was laid down as huge deposits of "banded iron ore" The great rust. (1)
This is hard to get an exact number on, but as far as I know, it is estimated to have taken at least 500 million years.
And then oxygen increased again, a billion years later (2)
It was not fast. It was measured in 100 million year ticks.
1) https://en.wikipedia.org/wiki/Great_Oxidation_Event#Banded_i...
2) https://en.wikipedia.org/wiki/Neoproterozoic_oxygenation_eve...
Faster? Do you have an example? What species can add 10^12 tons of any chemical in just few hundred years?
There were geological events and asteroid impacts that may result in more dramatic changes, but their signatures will be different.
Indeed. We might finally start getting some real estimates for those factors in the Drake Equation.
>we are only aware of one species that developed civilization building capabilities.
well, the first one just doesn't leave any chance for any other one.
>Life might be very common, but intelligent life still be incrediblY rare.
the time period between big ape and nuclear bomb is extremely short - few millions years. In a hundred or a thousand - doesn't really matter - years we'll be an interstellar species or may be we destroy ourselves by Covid-2319. The point is that complexity develops exponentially and tremendous changes are happening in an extremely a short period of time - i.e. if life has 4B years to develop when it most probably has 4.01B years to develop civilization.
Unlikely we will ever be interstellar. The technology involved is speculative and the physics barriers needed to be surpassed are impossible and not well understood.
To reach another star by the laws of physics involves many human lifetimes and that’s just the nearest star.
That in itself makes it more likely that we will never be interstellar.
"Roundtrip Interstellar Travel Using Laser-Pushed Lightsails"
https://ia800108.us.archive.org/view_archive.php?archive=/24...
We can disperse intelligent machines. Possibly with the ability to regenerate biological life.
Slow but plausible starships can be designed with 1960s technology. The obstacle is not the technology but the scale of the effort, a problem that could be solved by extension of civilization into the solar system with much larger populations.
https://galileo.phys.virginia.edu/classes/109.jvn.spring00/n...
Humanity will never put effort into this. We don’t have the technology yet but yes we can develop it but doing this is harder than building a bridge across the ocean between Asia and the US.
That bridge is also within our technological capacity. But it’s not happening period.
That depends on the scale of human society, doesn't it? Grow the population in the solar system enough and it becomes a smaller fraction of gross output than many trivial and frivolous things are today.
I'm arguing here that if non-interstellar space colonization is possible, interstellar colonization is a natural and feasible extension. You might argue that even colonization in the solar system will not occur, and I admit that's a defensible position.
>The technology involved is speculative and the physics barriers needed to be surpassed are impossible and not well understood.
we can build with today's tech - classic nuclear reactor plus ion drive - a 3 stage ship reaching 1000km/s, 1200 years to the closest star. Once we get to fusion, we'll be able to improve that speed a small order of magnitude.
>To reach another star by the laws of physics involves many human lifetimes and that’s just the nearest star. >That in itself makes it more likely that we will never be interstellar.
That is exactly what makes it _inter_stellar:) We'll have generations - 10-15 to the nearest star with the current tech mentioned above - of people living their lives on those ships. Living on a planet will become a strange thing for them.
I think in 10-20 years, once launching into LEO becomes cheap with Starship, companies, universities and wealthy individuals will be launching solar + ion drive and nuclear + ion to all the places in the Solar System and some automated probes - beyond.
Intelligent life most like arose from the extinction level events that wiped out less intelligent super predators. This gave those who are far weaker but with higher brain capacity the chance to express their genetic variations.
Not to take away from you personally, but civilization as we understand it is our own cliche.
Organisms developed on different planets could absolutely have a different view on life and society in general. Even on earth we have highly intelligent and physically capable organisms that care naught for your conceptions of how groups should function together. There are even organisms that seem to have no intersection with our set of interests that are way more successful in terms of populating earth and invading space. Putting our understanding and interests at some panacea is just hubris.
Regarding populating earth and invading space.
I was just watching the original (first) matrix movie yesterday because I was just too bored.
And there was this dialogue by Agent Smith:- ```I’d like to share a revelation during my time here. It came to me when I tried to classify your species. I realized that you’re not actually mammals. Every mammal on this planet instinctively develops a natural equilibrium with the surrounding environment but you humans do not. You move to an area and you multiply and multiply until every natural resource is consumed. The only way you can survive is to spread to another area. There is another organism on this planet that follows the same pattern. Do you know what it is? A virus. Human beings are a disease, a cancer of this planet. You are a plague, and we are the cure.```
So yea, I totally agree with you because just as how Agent Smith compared Humans to a virus and just like we know that not every living thing is a virus, In a similar fashion, I think not every species have intersection with our sets of interests (populating earth,invading space).
I actually had just watched matrix for agent smith actually. I don't know why but the guy looks really cool to me for some reason.
It's a cool speech, but it's also wrong. Mammals don't "instinctively develop a natural equilibrium", reality forces that equilibrium on them. A species gets too good at breeding and/or resource consumption - that's either happy times for their predators who eat them back into balance, or they starve themselves back into balance.
yea but we don't have predators thanks to fire.
I mean game theory and equilibria are universal. I don’t see why the basic rules of civilization would not apply to any level of organism sophistication.
Yes, but what we live in is well beyond a decision with four outcomes and all this assumes "we are doing it right".
Maybe technology development is not exponential but s-curve. And anything large scale is impossible. So outside some radio signals there would not be any grand things that could be observed.
This is where the discussion, as it always does, silently transitions from science into science fiction.
We know absolutely nothing about extraterrestrial life. We can only project our own singular experience onto the rest of the universe. We only have one data point. There is no scientifically acceptable method of induction from a single data point. The possibilities are endless, and are capacity to narrow them down becomes warped by our love of stories and the kinds of art that we have created about extraterrestial life, all of which are in one way or another metaphors for the human condition.
There is nothing wrong with saying, "Anything is possible and we have 0 evidence allowing us to narrow it down." It isn't fun, but it's true.
Dark forest hypothesis explains this in a “dark” way. They exist but are smart enough to hide from hostile hunter/predator life forms. Meanwhile our dumbasses are blasting radio signals into space like a little kid trying to talk to every stranger they see.
Dark Forest depends on the presumption that interstellar travel is worth engaging in (ie it's possible to do faster than light), and that spectacularly devastating weapons are possible. So far we have no reason to believe that either of those assumptions is smart.
Faster than light travel isn't needed (and IIRC doesn't occur in the series the dark forest name comes from). Spectacularly devastating weapons are definitely possible - redirect an asteroid into an inhabited planet and you're likely to kill most of its inhabitants; redirect enough and you can kill almost everything. That's not even getting into things like antimatter, gamma rays, etc. The dark forest hypothesis doesn't need destruction of solar systems to be possible, just severe damage to civilisations.
> and IIRC doesn't occur in the series the dark forest name comes from
The Trisolarians developed FTL travel while they were on the way to Earth, IIRC.
I tried to look it up. I think they didn't ever get FTL, based on https://www.reddit.com/r/threebodyproblem/comments/1blvikg/c... and https://forums.spacebattles.com/threads/trisolaris-in-wh40k.....
Ah, yes, you are right. They managed to speed up their travel time to Earth greatly, but they did not reach or surpass the speed of light. I have to read the trilogy again.
They had the sophons which allowed them to convey information via quantum entanglement, i.e. instantly.
They - and the humans - developed close to light speed traveling which IIRC has the same underlying mechanics as that blackout-galaxy-safe-space thing which is the message that your civilization is not harmful.
It's also largely bunk. More a story than a hypothesis, really. Game theory shows cooperation beats aggression on a long enough timescale. Politics shows alliances and MAD deters first strike. Even actual "dark forests" are full of animals that have bright colors and make loud noises.
I really wish natives of places we discovered knew about this. they could've evaded all the bad parts and just explained how it is just a story.
The Indigenous peoples of the Americas knew well enough about the value of cooperation and alliance. That's why they had stuff like the Iroquois Confederacy, and switched between working with the British, the French, and the colonies depending on which was best for each individual group of natives at any one time. To present them as pure victims powerless before the might of white settlers undermines the political and cultural agency that Native peoples in fact had, and exercised.
The predominant form of relationship between European and Native American peoples for hundreds of years was trade, not war. The tragedies and the atrocities that resulted were a slow burn of conflicting interests and epidemiological naïveté, both between Europeans and Natives and also within each group. That's quite different from the hiding and decapitation strikes usually presented as "dark forest hypothesis", because there's no reason that those specific interests and ignorance would carry over to interstellar society (and every reason that they would need to be overcome in order to become interstellar in the first place).
But why do people always use the fate of resource-constrained preindustrial societies (both Europe and America) to try to predict relationships between hyper-advanced Kardashev-level civilizations anyway? It really seems to me like some kind of projected shame. You can see this too with Liu Cixin. He came from a country that was recently dominated, and has more recently been preparing to dominate its neighbors, so his story pretends nothing better is possible. I suppose that's comforting for some, and questioning it brings out people who show what it's really about.
Google Trends shows the top 10 countries for "Dark forest hypothesis" include the US, Taiwan, China, Peurto Rico, HK, Canada, and Aus [1]— Places with a prominent recent or ongoing imperial history, whether as victims or victimizers. I actually find the "dark forest" narratives quite disturbing, not as a prediction of our future, but as a window into the psyche of people who seem to want it to be one.
You might as well say the Romans had a slave-based economy, so therefore spacefaring empires must also be looking for human slaves! That's got exactly the same amount of validity as the Native comparison. But economic and military incentives obviously change as technology and culture develops. If anything, the fact we used to kill a lot of natives, and we don't so much anymore, is a strong sign that advanced societies can trend towards being less genocidal.
1: https://trends.google.com/trends/explore?q=%2Fg%2F11jyk5h9nj...
Valid arguments tbh. In the struggles between European and Native American, there is the aspect of being able to escape and continue to pose as a threat and such. There is no total extinction. But in dark forest theory there is the total extinction of home planet aspect, without giving in your own location (no vengeance or kill switch can be carried towards you). And also attack factor being so much more advanced that there is little to no defense against it.
In our world, we never had this level of capability amassed in one hand. We were never tested in this scale. But lets think there was a button in cold war that completely erased soviets with no harm to planet, no harm to the western world and without anyone noticing the origin of this action. How many in U.S. would press that button? I think we would've pressed many times. And later, to know that another planet might be having a button exactly like this that they can press and erase us? we would press first so they never get the chance to do it. Paranoia and self preservation prevails, sadly.
I believe our cooperation in society also relies on our capability of projecting power be it physical or economical. The weaker individuals power becomes, the louder powerful peoples actions become. Saying this as Non-U.S citizen, right now the richest guy can easily interfere in state dealings, act like the president in a way, maybe this is evolution of lobbying tradition there but could you imagine such a thing happening in ancient Greece or even in Rome? What prevented this was citizens' ability to exert power. Right now there is little of that, power disparity is huge and so there isn't as much of a cooperation. Sorry if this part deviated from topic or smth. It is just I believe it 100% depends on real, physical factors rather than how advanced we get mentally.
Cooperation depends on you and your potential allies surviving long enough to be able to contact each other, and being strong enough to counter the threat. We don't know whether we will develop capabilities fast enough to counter an enemy that e.g. at the first sign of radio started accelerating a bunch of super-dense (hence small, hard to detect and stop) kinetic kill devices our way.
MAD is utter bunk. It depends on rational actors that also believes the other actors are rational. Even Reagan realised the folly of MAD after Able Archer in 1983, and realising the Soviet leadership genuinely seemed to believe the US might be prepared to strike first. If either side thinks the other side is irrational and preparing a first strike, MAD falls apart. If either side is actually irrational, it also falls apart.
But MAD also depends on a sufficient ability for both sides to do serious harm. If one side sees a first strike as an opportunity to prevent the other side from gaining that ability, MAD also falls apart, and the thinking behind it can again then push a rational but callous actor to strike first to prevent being pushed into a MAD scenario.
Cooperation might eventually win out, but that won't help you if your civilization has long since been wiped out.
Cooperation only depends on anyone, in the history of ever, having at any point survived long enough to contact each other and form an alliance. Once a critical mass of parties that prefer cooperation has been reached, all future cooperative parties are at an automatic advantage over aggressive parties.
You can see shades this of this, e.g., in the difference between single-round versus iterated Prisoner's Dilemmas.
> MAD is utter bunk. It depends on rational actors that also believes the other actors are rational. Even Reagan realised the folly of MAD after Able Archer in 1983, and realising the Soviet leadership genuinely seemed to believe the US might be prepared to strike first.
What do you think the long-term prospects are of a species that goes around flinging RKVs at people? No more North America and no more Eurasia, if that happened. Maybe South America and Africa can pick up the pieces. Just because irrational hyperaggressive actors can briefly exist doesn't mean you're likely to encounter them. They won't survive for long.
MAD exists whether or not any particular participant believes in it, because it's just the cause and effect of competing powers each with their own agency. Or else we wouldn't be here. Even the Soviets knew that a possible US first strike was better than a guaranteed US retaliatory strike, which would happen if they struck first.
> Cooperation might eventually win out, but that won't help you if your civilization has long since been wiped out.
The whole "Fermi Paradox" arguments are based on an extreme form of "eventually, we should expect to see aliens, so why haven't we already?" This doesn't mean aggressive civilizations don't exist, but the reasons to think they're prevalent are overblown.
> all future cooperative parties are at an automatic advantage over aggressive parties.
No, that does not follow, because it assumes any cooperation gives sufficient leverage to be able to resist. But an enemy lobbing kinetic kill devices at high speed from locations that does not give them away would require far more advanced tech to stop.
> What do you think the long-term prospects are of a species that goes around flinging RKVs at people? No more North America and no more Eurasia, if that happened. Maybe South America and Africa can pick up the pieces. Just because irrational hyperaggressive actors can briefly exist doesn't mean you're likely to encounter them. They won't survive for long.
On Earth. In space, throwing kinetic kill devices at people won't affect your own territory, and can at least in theory be done without any possibility of tracing it back to you - you "just" need to accelerate a bunch of them outward to starting positions far from your home system. Any civilization smart enough to be able to build devices like that would be smart enough to build autonomous ones that would become operatonal first when in a position that wouldn't give them away.
> MAD exists whether or not any particular participant believes in it, because it's just the cause and effect of competing powers each with their own agency. Or else we wouldn't be here. Even the Soviets knew that a possible US first strike was better than a guaranteed US retaliatory strike, which would happen if they struck first.
The point of the lessons Able Archer is that there were strong indications the Soviets thought there was a line at which point a first strike to preempt a US first strike would be preferable, and that they thought they were getting close to that line.
> The whole "Fermi Paradox" arguments are based on an extreme form of "eventually, we should expect to see aliens, so why haven't we already?" This doesn't mean aggressive civilizations don't exist, but the reasons to think they're prevalent are overblown.
I've seen nobody suggest we have strong reasons to think they are prevalent. That is missing the point. It's one of many possibilities, but one where the temporary existence of even one in any given "neighbourhood" close enough to strike before we've gotten advanced enough to defend against compact kinetic kill devices hammering us at a decent percentage of c (or worse options we don't know about) would mean we'd already be doomed without knowing about it.
It doesn't even need to be a long-lived one. There just need to have been one alive when our first radio signals hit them.
It doesn't even need to successfully kill most civilization. For it to resolve the Fermi Paradox, attacks just need to happen often enough that those who survive quickly decides hiding is the best option just in case.
I often wonder if the answer to the Fermi paradox isn't just as extremely banal as "turns out that interstellar exploration just isn't economically viable". I think it's entirely plausible that advanced economies are circular, and that within a circular economy, it's just extremely difficult to justify the massive expenditure of resources that it would take to become interstellar.
I mean, think about how many stars had to align to catalyze our first steps on the moon. Now, 53 years later, we're just starting to put serious effort into going back -- not because there's any market reason to do so, but because (once again) there's political pressure for it. Which would suggest that the best case scenario for the current exploration efforts are something along the lines of what we already see in Antarctica: a well-staffed scientific presence that does really cool/valuable work, but nothing remotely approaching even a single major city in terms of human presense.
It seems to me that one of the unwritten priors to the Fermi paradox (at least in popular discourse) is that technology is the only prerequisite to expanding a civilization; in other words, if you have the technology, then interstellar expansion is only a matter of time, and that all civilizations will inevitably eventually develop the technology. And that... seems like a pretty big assumption, if human history is any indication.
The thinking generally would be that while it might take political pressure to initially begin leaving the home planet, once politics has unlocked that capability, commerce will take over.
If we were to begin mining the solar system, it unlocks vast pools of resources that would really change things.
That said, interstellar travel is still a pipe dream because of the time involved. Without finding a cheat code for physics, it may well be that intelligent life is always trapped in its home system and has to live and die within the limitations of stellar evolution.
Vast pools of /what/ though?
It seems, at present, that energy is more of a constraint on civilization than matter.
With unlimited cheap energy, there's enough material to do most anything we might reasonably want.
It's likely to cost $thousands/kg to bring materials back from beyond Earth orbit. There are only a handful of elements valuable enough, and that's if they existed in pure form.
Hypothetically, if an asteroid made of pure gold existed, and if a Cargo Dragon atop a Falcon Heavy had enough delta-V to make it there and back with a couple of tonnes, it might break even, but all of this is doubtful.
Most valuable minerals are worth hundreds to low thousands of dollars per kg, so you need a launcher that can bring back a ton of rock for $1M - and not from LEO, you probably need to escape Earth's gravity and get back again.
The physics and engineering are proven, but the economics? Unlikely.
Put another way, you can mine a heck of a lot of Earth rocks with a rocket's worth of kerosene.
53 years is instantaneous on cosmological time scales.
I thought it might just be the rocket equation. Bigger planet = very little of the rocket is payload.
If most planets are bigger than Earth, then most civilizations will be like "muh we can do it but what's the point?" and they'll be content with just having a few science experiments in orbit, and that's all.
If life is quite common, that still leaves an option that we are among the oldest of civilisations.
Besides, lack of comical presence doesn’t necessarily mean demise: maybe all face the problematic consequences of uncontrolled industrialisation and go solar punk?
Even if civilizations are relatively common (which, as others have pointed out, doesn't necessarily follow from life being common), the distances involved are really huge.
We have some ideas for crossing huge distances, but none of them are really practical. There are ideas for accelerating tiny probes with light sails, but when we manage to send them somewhere with 90% of the speed of light, we have no way to decelerate them again in a controlled fashion.
What I want to say is: there's good reason to think that doing anything over 200 light years or so is just infeasible.
Now look at the night sky. The chance that you eye will detect a star at any given patch of sky that is roughly the size of a star, is nearly nill. That is not bad news for those who wish to see that stars continue to exist - it is a feature of the size, vastness, and expansion of the universe. Same for life, presumably.
Say another human-like civilisation existed and was more technologically advanced, what sort of tell-tale signs do you expect to see?
Scientists use the term "technosignatures", which you can google for more info. But broadly: radio signals, infrared from megastructures, optical signals like laser pulses. We haven't put a huge amount of effort in searching for such signatures, but there has been some.
Another possibility is we're looking for the wrong techno signatures, or just haven't conceived what the technosignatures for a 10,000-year technologically advanced civilization are.
We've been a techno-civ for what? Maybe only 200-ish years? Our paradigm is gobble up all the energy and grow at all costs. So extrapolate that out, and the logical conclusion is a dyson megasphere that radiates all over the infrared.
But then again, that paradigm is careening us towards an environmental and ecosystem collapse: the hunger for infinite growth is warming our climate, it's unclear whether our nuclear-armed social structures can handle the coming disruptions and migrations, and if we don't kill ourselves, unclear how big a population all the environmental degradation and pollution can support.
So we can project our cute 200-year-old patterns out to a maybe-discoverable 10,000-year civilization driven by the same motivations and flows, but those extrapolations quickly run up against some pretty existential pragmatic threats.
Maybe the answer is we aren't seeing any of the technosignatures because the techonsignatures on the other side of the Great Filter look very different from the ones we conceive of now.
Thing is, though, it kind of assumes megastructures. AIUI Earth is already getting less radio-noise-y, as fibre-optics take over, and would be difficult for us to detect from the next star (at least to detect the technological civilisation; the biosignatures would be obvious).
Maybe people just don't _actually_ build that many megastructures.
I’m personally not convinced advanced civilizations would necessarily exhibit such technosignatures at all. I even go as far and ask are you sure if an advanced civilization was living and mining in Saturn’s rings we would even notice? If one considers the scales of things and realizes how big the Saturn system is relative to Earth then I doubt they can be so confident we would even notice our neighbors in the solar system yet.
no matter how advanced the civilization is, proxima centauri will always be 42 trillion kms away. Our civilization in current stage is not even close to 0.1% the speed of light but lets say your advanced civilization goes at 99% the speed of light, still doesnt change the fact they need 4.25 years approx to reach earth. Still doesnt change the fact that unless they have a 1 billion km wide telscope, they cannot reliably tell if earth has life or not. So basically you are asking them to take a shot at coming to the solar system on a 5 yr trip when they have no idea what is found here. Now extrapolate the numbers for the average 100 light year trip between 2 points on our galaxy and you ll quickly realize why we dont have aliens
On a similar note, humans cannot colonize the galaxy. Sending a single message across would take thousands of years. Instead a human ancestor would split into various individual species.
When you think of it, light speed is really slow. Even on Earth we are capped by it.
> Still doesnt change the fact that unless they have a 1 billion km wide telscope, they cannot reliably tell if earth has life or not.
How come we’re making progress on this without a 1bn km telescope?
And even that notwithstanding, they could use a solar foci telescope. It's kind of a pain to orient, but it /does/ give you extreme magnification.
Where did you get the 1bn km number? I'm asking it seriously, I'd like to better understand how to calculate these things.
some calculation about resolution of the telescope to be able to see cities and people of another planet from a 100 light years away at the minimum. I forgot the exact calculation but it ll need a humongous sized telescope mirror
If their lifespan is 10,000 years, a five-year trip to exotic backwater Earth would be just a vacation.
Direct Multipixel Imaging and Spectroscopy of an Exoplanet with a Solar Gravity Lens Mission (with 1 km resolution)
https://arxiv.org/abs/1802.08421
...and someone made an awesome video about it:
https://www.youtube.com/watch?v=NQFqDKRAROI
If they came here and back at .99c it would be ~70 years "time debt"[0] for them (meaning 70 years would have passed for their relatives back home).
[0] Terminology from Dan Simmons's Hyperion. Would also recommend Joe Haldeman's The Forever War for more time dilation themes.
> relatively strong evidence that life, while common, isn't long-lived.
https://en.wikipedia.org/wiki/Great_Filter
I always thought that how far things are in the universe and the impossibility of faster than light travel were enough to explain why life might be abundant in the universe yet we never observed it.
The probability of advanced civilization is given the probability of life is quite low itself.
For the overwhelming majority of time life has existed on earth only a minuscule part of it involved civilization. And an even more minuscule part of it involved technology that has a small chance to send a coherent signal to another star.
Our future is easily estimated by the hardness of traveling through space and the demise of our sun. Probability points to the end humanity by way of the death of our star. We are statistically most likely to end.
We don't have to look to the stars to tell that humans have a horrible tendency to make the majority's life a struggle and constantly balancing on the verge of demise.
Maybe they just don't feel the need to blast their emissions all over the sky like some sort of a caveman.
Our own technological signature is coming to form a very thin shell. Once we switch fully to fiber optics, lasers, and beamformers, there won't be any aliens learning English from listening in on our TV transmissions anymore. Radio broadcasting was cool, but also horribly wasteful.
It's probably incorrect to assume that more technologically advanced civilizations would be louder.
Not so! Humans are just early: https://www.youtube.com/watch?v=l3whaviTqqg
It's extremely likely that our demise will come before too long.
The problem is that "before too long" is on a universal timescale, not a human timescale.
Humanity could exist for a million times longer than it already has, expand to other planets in our solar system and even to another solar system or two, be wiped out completely, and on the appropriate timescale we were absolutely "short lived."
I see it differently -- if we are all alone, then our disappearance will be an unfathomable catastrophe. If it's abundant, well, so it goes.
What do we mean by alone?
Life isn't this "magical" force. Life is just an outcome which is just incredibly rare. Or maybe its not? Maybe we are just too primitive in the sense that we haven't analyzed all planets (like this planet is just 120 light years away, still huge but still, who knows how this search continues, and maybe we can even find more/maybe advanced species as well?
But also, as others have pointed out. I think that getting to civilisation level is pretty rare. Its not like the signs on this life that we have found automatically means that they are one day going to be a civilization level life. They may or may not & so many other comments above this comment have beautifully shown the amount of rarity in that which was the major takeaway from this HN atleast for me.
Its still just so fascinating how human societies exist. Maybe I am pessimistic, but like we believe in gold because everyone else does, but for the first time ever, Imagine the people who started trusting in gold and started trading in gold.
They couldn't eat gold, For all its worth, they might have thought that its just shiny rock and its abundant, we just haven't discovered it yet and its going to be worthless so we might as well use grains.
But such trust in gold,maybe even religion/ general trust on society structure beyond the people you know directly is just so bizarre. People believing and dying for nations made those nations have power. And now we trust those nations and their power because our ancestors said so & taught us so. I have read sapiens book 4-5 years ago and I think I had never wondered about such things until now.
Our ancestors could change things way more radically. They had such freedom.
Voltaire used his reason to pursuade people for a revolution.
I am not sure, but in the vastness of the internet, people have just stopped caring about reason but rather all they care about is authority. Change fears so many people.
People would know that some things are bad yet just because they exist, they think it as something so highly and won't even conceive of the possibility of fixing it. And others would be peer pressured into we can't change it. And the people who want change would be ridiculed and made fun of. So much of the time, reason falls off on dead ears in today's world & emotions are hijacked by echo chambers.
Much of our society(I can't say nobody,because I would do grave injustice to people who reason) wants to reason because we want the comfort of emotion.
Also even if it's low, it's not impossible that human technology actually is the one with the more advanced in its observable part of the universe.
That is, if there is supposedly one civilisation with clear advance in technology, it could just as well be humanity.
The thing is we've only been around a tiny period of time, and given the size of the universe, it would have to be an amazingly tiny Goldilocks zone in time to actually notice us, let alone do anything about it.
> millions of years more technologically advanced than us
> should be leaving telltale signatures across the sky that we'd likely have detected by now
I'm not sure the second follows from the first. What if they're hiding?
Conversely, it should mean there would also be lots of civilisations millions of years technologically behind us. We're more likely to be an average civilisation than the least-developed
Bostrom's trilemma and the notion of the Great Filter!
But in the grand scheme of things, even its "bad news" just ONE datapoint of life elsewhere is at least something to start working with.
> that is probably bad news for us.
Apart from the Sun, the nearest star to us is four light-years away. I'm not loosing my sleep on the thought of being "discovered" by anyone over there.
Most of the sky is left unexplored. I think it’s premature to suggest we don’t see things. There are too many things to see in a single lifetime.
But if there was a Kardashev type III civilization in the Milky Way, they would have had full control of our entire galaxy in a mere 200 million years or so. And we can be pretty sure that such a civilization doesn't actually exist. Which suggests that either advanced life is rare, or dies off long before it ever reaches such technological breadth.
Or this is merely sci-fi and it's physically impossible to build anything even close to such structures as Dyson spheres. There is no reason whatsoever to believe that just because we can conceive of something like that, it's actually possible to build it using real materials in real quantities with real amounts of available energy in a star system, and even less so to maintain these magical devices even if built.
you don't need to build a physical shell, a dyson swarm would get the job done.
Considering the distances between stars, we might not see civilization spreading as coherent empires but more like humans spreading through the islands of the pacific archipelago. Certainly the same species but also culturally seperated to develop on their own.
Unless faster than light travel or communication becomes avaliable, it might not even make sense to travel through the galaxy.
Maybe they have different motivations than humans because they are aliens.
Someone has to be the first. Granted, us being first is extremely unlikely. But the same is true for whoever it ends up having been.
Maybe there's some truth to Douglas Adams' writing - we are just insignificant enough that nobody cares. In the Star Trek series it's similar, they are interested to see how pre-warp civilisations develop, seeing them as quaint, but that's it.
> Far out in the uncharted backwaters of the unfashionable end of the western spiral arm of the Galaxy lies a small unregarded yellow sun. Orbiting this at a distance of roughly ninety-two million miles is an utterly insignificant little blue green planet whose ape-descended life forms are so amazingly primitive that they still think digital watches are a pretty neat idea.
> And the absence of those signs would be relatively strong evidence that life, while common, isn't long-lived.
If dark forest theory is right, alien civilizations may stay undetectable by hiding biological signatures of their worlds.
The dark forest theory makes for a great book premise, but it probably doesn't apply in real life simply because the distances are so far.
The universe is not a forest. It's a gigantic, empty ocean. The next, dangerous tribe is not lurking behind a bush 2 meters away, but is sitting on an island that's so far away it will take centuries to go there, if it is possible at all
Isn't that the point of the dark forest theory? It's not the fact that there is a dangerous tribe behind a bush it's more that you don't know if they're dangerous or not so you have to err on the side of caution - because you don't know if they're doing the same.
It's the whole chain of suspicion theory that it's safer to shoot first and then ask questions later because the speed you can communicate is the same speed you can mount an attack.
Yes, but the next bush is dozens of light years away. The analogy breaks down because the distances are different in quality.
The only reason why this becomes such a problem in the Three-Body-Problem is the existence of magic in that universe. Thinking protons, instant communication, folded dimensions, easy interstellar travel, it's all interesting speculation inspired by physics, but incompatible with our actual universe.
How do you know it's incompatible with the actual universe instead of our current understanding of the universe?
Take us for example, we're communicating instantly (for practical purposes) using thinking machines - how would that not seem like magic to someone thousands of years ago?
My point is, we don't know what the tribe have behind the bush. It's the equivalent of the Mayans wondering what's over that hill and then finding the Spanish with gunpowder, horses, and steel armour.
The only reason why we can't out sentient protons folded out of 28 microdimensions into our 3 macrodimensions is the same reason we can't rule out that our universe is actually the works of a giant hand puppet player called Zquaarx.
The problem is just - if any of what happens in 3BP was to actually happen, we would not have to be a little wrong (like Newton was in regard to celestial mechanics) but so wrong that it doesn't even make sense to apply what we know at all.
This is, by the way, the exact point of the first part of the first book: physicists discover that all off the known physics are completely wrong.
Why does the distance change the dynamic? So what if the species trying to exterminate you are 500 light years away, you think they should ignore it ? Maximum travel speed of an extermination weapon in 100,000 years of of science may very much be impressive or even magical by today’s standards
The distance completely changes the dynamic. If I tell you there's a crazy axe murderer in your house, you should be afraid. If I tell you there's a crazy axe murderer on Venus, how afraid are you?
And unless we are completely wrong about physics, the maximum speed of a weapon will be the same as it today - very close to 1c.
Those things are just sci-fi glitter absence of which doesn’t invalidate the theory.
Time does not matter. Space-faring civilizations can adapt their pace of life to the communication and exploration speeds or even live at multiple speeds. They are likely energy and resource-bound: within the same theory Dyson sphere is a risk, so they can only consume a fraction of locally available energy to remain unnoticed - meaning that it’s not the distance but energy consumption that will limit them.
Of course, the risk is, thinking that centuries is a long time may be merely a human, and not a universal, trait.
And the evidence of that is what? What is the mechanism behind that? How is it testable?
This is what annoys me about this field. It is just magical thinking and baseless speculation. Random ideas get given names like "dark forest theory" like they are deep and consequential.
What you said is the only consequence of that "theory", because that "theory" is literally just the idle speculation that "alien civilizations may stay undetectable by hiding biological signatures of their worlds."
It’s game theory, mathematics. Let’s say every player has 3 actions: do nothing, expose yourself and destroy the player you aware about. Your goal is survival. If you expose yourself in this game and there’s at least one player choosing „destroy“ action, you loose.
Now, of course there’s a question of applicability of this model: 1. are there other players? (if the game started, we won’t know until we observe destruction event - but that’s falsifiability) 2. do they have means to destroy you? (we may find out) 3. do they have motivation to destroy you? (we may find out) 4. can you protect yourself against unknown level of technology? (we may find out).
This theory meets scientific criteria, it’s just that those criteria require level of technology that we may not reach in thousands of years.
Dark forest theory is wrong. Staying undetectable is always inferior to both staying undetectable and safely deploying varyingly detectable decoy targets at safe distance to probe the situation and gather intelligence.
Deploying decoy target requires more advanced technology (space travel) than hiding the signature (we may be able to do it long before we reach another star). I don’t think this is a good argument. Let’s say, some civilization decides to invest in decoy. It needs to shine brightly, the energy footprint is huge, a lot of work has to be done to transform the entire system. Then what? If there’s a hostile player, capable of destruction, they research and destroy the target, and start surveying the neighborhood. You cannot just build a decoy on another end of the galaxy, right? The further you have it, the more complicated is the task. And then you can only hope that the time left will be enough to collect enough energy (even if you have the tech) for defense.
Dark forest theory is about very advanced civilisations not engaging with anything around them. Limited resources are not an issue in this case. You can easily just do everything in parallel with AI or other automated control system, using stars as energy sources, including spawning whole decoy civilisations at different stages of development. Because we see so many stars we know nobody is running out of energy yet.
Possibly a more advanced civilization than us has long understood that it should not try to contact and bother other ones, but rather focus on their happiness where they are
There is no way civilizations make it past a certain point. It’s so completely obvious, just look at our world. In 2025 we are enabling a genocide while the masses don’t seem to care or even know about it.
You think the people that are having these types of atrocities committed against them would think twice about ending civilization as revenge if given the power? What do you think is going to happen with AI?
If we can’t stop a genocide, why would you think we can stop civilization ending?
>It means that civilizations should exist that are millions of years more technologically advanced than us; and should be leaving telltale signatures across the sky that we'd likely have detected by now.
Or they've reached their technological plateau millions of years ago. Like we did 50 years ago.
>And the absence of those signs would be relatively strong evidence that life, while common, isn't long-lived.
We know for a fact that life have existed on Earth for >2 billion years.
> Or they've reached their technological plateau millions of years ago. Like we did 50 years ago.
What a bizarre thing to say, considering this very discovery leans on decades of science and engineering over the past 50 years!
None of those discoveries help with space travel whatsoever. Our most advanced space propulsion still works on the principle of throwing a lump of matter in the opposite direction. The rocket equation remains undefeated. Special relativity remains undefeated. This is the plateau that I'm talking about. And we have zero idea if anything can be done about it.
Many trolls hiding in these comments... either that or they just dont understand what the scientific method is.
Not sure how bad it could be given the hypothetical "millions of years more technologically advanced". They'd need to have a pretty good reason to care about us. Otherwise, we'd be so insignificant that it seems much more likely that whatever natural resources they'd want, would also be likely nearer and easier to obtain.
War-mongering, and otherwise zero-sum mentality shouldn't make all sense if they have the technology to actually reach us. [3-body spoiler warning] Kinda like in the Three Body Problem. It was kinda silly how advanced the Trisolarian were, while still bothering traveling to earth, rather than approach the problem in any number of more obvious ways
in the book they couldn't stay in their system since it was unstable and our star was the closest to them and they knew we were less advanced than them.
Did you read the parent in haste or did they edit their post? They said:
> [1] It means that civilizations should exist that are millions of years more technologically advanced than us;
> [2] and should be leaving telltale signatures across the sky that we'd likely have detected by now.
> [3] And the absence of those signs would be relatively strong evidence that life, while common, isn't long-lived.
> [4]Suggesting that our demise too, will come before too long.
So they were talking about the great filter, not alien invasions, which is what you appear to be replying to.
> millions of kilometres away
Yes, millions, but that's a major understatement.
It's 124 light years away. Which is around a million billion km away. (a.k.a quadrillion)
It's just so damn far.
My prior is that life is not uncommon in the universe, multicellular eukaryotic type life less common and intelligent (whatever that means) life less common still.
If the closest prokaryotic type life is 100 light year away then the the closest intelligent life might is pretty far away.
I base this on almost nothing - other then the time it took for prokaryotic and eukaryotic life to emerge on Earth; which to my mind is surprisingly quick for the former an weirdly long for the later.
> an exoplanet millions of kilometres away
Not millions, not even billions. 124 light years is about 10¹⁵ kilometers, or a million billion kilometers.
> given how incredibly unfathomably vast the universe is ... we ...
But the probability of developing a highly developed civilization can be much, much smaller than 1 / number of planets in the universe.
Even the probability of developing any life at all might be. We simply have no idea how rare it could be.
> It just seems so unlikely that we are somehow that special.
Our ability to think about those matters is conditional on emergence of intelligent life. That is our observation of ourselves is compatible with any probability of emergence of intelligent life (including almost never that is p=0).
Trillions of kilometres away!
The universe is so big that even very rare anomalies are common. There is life outside of earth, that is all but confirmed.
> It just seems so unlikely that we are somehow that special.
That prior is formed by sci-fi media, not science.
> I always felt it overwhelmingly likely that it developed elsewhere too
"Life" is an information complexity characteristic. We know that information complexity is not uniformly distributed in the universe, and in fact the vast majority of the universe is extremely information-poor. Logically from the scientific data you'd assume that "life" in the universe also has a very lopsided distribution.
The only place we know for sure life exists on is Earth. You can't reason about the likelihood of life existing elsewhere with a sample of N=1.
deduction, induction, abduction
I never got this. Someone eventually wins the lottery. Someone eventually gets struck by lightning. How lucky a lucky person feels doesn’t influence the cold hard probabilities. So this feeling is mostly a delusion.
And frankly we don’t know how probable or improbable it is for life to form because we aren’t actually clear how it formed in the first place. The fact that the event has not and can’t (so far) be reproduced by us means that it is already highly likely to an extremely low probability event.
The question is how low? Low enough such that there is another planet that has it within 124 light years. I actually don’t think so.
I think the probability of finding a planet that has biosignatures of life but doesn’t have any life at all is a higher probability then actually finding planets that actually have life. No matter what you think the likelihood of finding life is, I think most people agree that the above should be true.
[dead]
we are alone as God only populated earth.
Interestingly we can’t actually know that we are correct in our calculations of what a planet lightyears away has as its atmosphere because we will never be able to go there and make sure we are correct. It’s a calculation and nothing more. For all we know that planet may not even exist. That’s what’s mind blowing about astronomy. We really don’t have any way of proving anything about what we are observing. All we can say is we are observing. That’s the only thing science can offer us.
Spectroscopy is well established.
Some speculation
On DMS:
- DMS is a very specific configuration that’s rarely the endpoint of non-living chemical cycles.
- The simplicity of DMS doesn’t make it less indicative of life—it actually makes it a very selective molecule, which only shows up in large quantities when life is involved (at least in Earth-like chemistry).
- Until we find a compelling abiotic pathway, high DMS remains a strong biosignature, especially in the context of a planet with a potential ocean and mild temperatures
Possible origins:
We’re looking at some form of life that can:
- Thrive in a hydrogen-rich atmosphere
- Possibly live in or on top of a global ocean
- Generate large amounts of DMS—potentially thousands of times more than Earth
The closest Earth analogy is:
- Marine phytoplankton, particularly species like Emiliania huxleyi, produce DMS as a byproduct of breaking down DMSP, a molecule they use to regulate osmotic pressure and protect against oxidative stress.
- If something similar is happening on K2-18 b, we’d be talking about an ocean teeming with such microbes—perhaps far denser than Earth’s oceans.
Possibly "Giant photosynthetic mats" or sulfuric "algae"
If there’s some landmass or floating structures, maybe the DMS producers are:
- Photosynthetic, sulfur-metabolizing analogues to cyanobacteria
- Living in dense floating colonies or mats like microbial reefs
- Using dimethylated sulfur compounds in their metabolism, and leaking DMS as waste or signaling molecules
===========
Of course there have been lots of ocean planets in sci-fi literature, but I'm most reminded of the "Pattern Juggler" Planet Ararat from Alastair Reynolds' "Revelation Space" series.
This is incredibly exciting news!
> Of course there have been lots of ocean planets in sci-fi literature, but I'm most reminded of the "Pattern Juggler" Planet Ararat from Alastair Reynolds' "Revelation Space" series.
Erk. Couldn't you pick something from a less... apocalyptic universe? :)
The idea of floating mats of life reminded me more of Wang’s Carpets.
https://en.wikipedia.org/wiki/Wang's_Carpets
Or, megafauna. Some Leviathan in the deep.
Not that exciting until they find other different biomarkers.
Dead Comets have DMS: https://arxiv.org/abs/2410.08724
And the interstellar medium.... "On the abiotic origin of dimethyl sulfide: discovery of DMS in the Interstellar Medium" - https://arxiv.org/abs/2501.08892
"...Although the chemistry of DMS beyond Earth is yet to be fully disclosed, this discovery provides conclusive observational evidence on its efficient abiotic production in the interstellar medium, casting doubts about using DMS as a reliable biomarker in exoplanet science..."
This planet is 2.6x larger than Earth and has concentrations of DMS "thousands of times stronger than the levels on Earth".
It would take a lot of cometary impacts to seed the entire ocean with that much.
From the paper [1]:
> Therefore, sustaining DMS and/or DMDS at over 10–1000 ppm concentrations in a steady state in the atmosphere of K2-18 b would be implausible without a significant biogenic flux. Moreover, the abiotic photochemical production of DMS in the above experiments requires an even greater abundance of H2S as the ultimate source of sulfur—a molecule that we do not detect
[1] https://iopscience.iop.org/article/10.3847/2041-8213/adc1c8/...
A bit clickbaity of OP to skip the operative word ‘promising’ signs of life.
To be fair, the original title goes above HN's character limit, but the omission is almost worthy of a flag, in my opinion...
Better alternatives:
- Promising signs of alien life found on a planet beyond our Solar System
- Astronomers have found promising signs of alien life on an extrasolar planet
And it isn’t actually signs of life. The first paragraph:
> Astronomers say they've found "the most promising signs yet" of chemicals on a planet beyond our Solar System that could indicate the presence of life on its surface.
This should be higher up
This is happening 124 light years away from earth.
That means if we develop a way to make a space ship accelerate at 1g for a long period of time, you could go there in just 10 relativistic years.
Unfortunately, whilst science allows such a rocket, our engineering skills are far from being able to build one.
Calling it simply an engineering issue is not properly conveying the ridiculousness of such a journey. For a small space ship of 1000 tons, this would take ten thousand times the current yearly energy consumption of mankind. So we'd need to figure out how to generate the energy and then store it on a space ship before even thinking about the engineering.
And that's ignoring the mass of the fuel. The classical rocket equation has the mass going exponentially with the velocity, which makes this endeavor even more mind bogglingly ridiculous. We'd actually need 2 million years worth of our current yearly energy consumption.
It's fun to think about, but being clear about the challenges puts quite the damper on it.
Seriously, most if not all of humanity's issue is our current energy wall. I truly wish we can invest more in energy as compared to AI because I truly believe that most AI agents are roughly the same and now are benchmark maxxing and even google's gemini is really really cool. Maybe now training it even further has less reward for the cost?
I truly wish energy could be a solved issue. I think clean energy can be great of two types, solar and nuclear, though nuclear can require a lot of expertise to build it once and operation costs, (I am not talking about the risk of nuclear reactor exploding since its just a fraction of current risks)
I personally prefer solar as its way more flexible though I am okay with nuclear as well
Mainly the issue in solar is of battery, if I understand it correctly. So We just need to really focus as a civilization to the humble battery.
I don't think there will ever be a time when energy is a 'solved' problem.
The more energy you have access to, the more uses you'll find for energy, and therefore the more energy you'll want to have access to.
It does not have to be a chemical rocket. https://en.wikipedia.org/wiki/Breakthrough_Starshot
I wasn't talking about chemicals.
My computation assumed an antimatter engine. Any drive is bound by conservation of energy and momentum.
I guess you wanted to object to an propulsion drive. Sure, you can do some fly by maneuvers or use earth bound laser propulsion, but I'm not convinced that it will put a dent in it for a regular space ship.
Also, the starshot concept won't help you with slowing down. I was assuming you actually wanted to exit the spaceship upon arrival.
While still ludicrously optimistic, there's a vast gulf between "20% the speed of light" and "constant 1g acceleration for 10 years", energy-wise.
> The classical rocket equation has the mass going exponentially with the velocity
This made me think that F = G((m1m2)/rr) is good enough to go to the Moon, but not good enough to give us GPS.
Maybe some discovery could help us build antimatter drives one day.
Our energy production grows exponentially. For a type I civilisation, producing that kind of energy would be possible. For a type II it would be trivial. In any case the timescales involved are measured in centuries.
That's mainly because our population roughly grew exponentially lately. That won't continue.
Energy production is not something self-amplifying like a population of rabbits, so there is no fundamental reason why energy production per capita should grow indefinitely.
But sure, how you would turn sunshine into antimatter at astronomical rates might be an interesting problem to think about. But my original point that basically dismissing this as an engineering issue is a bit dishonest still stands.
If you can somehow make a ship capable of constant acceleration at 1G, and had enough shielding on it to protect it against the radiation, you can travel to any point in the observable universe, in a human lifetime.
If you just keep accelerating and left as a 20 year old, you'd be in your 50s when you saw the final stars born and die in 100 trillion (earth) years time.
That's how crazy relativity and torchships are
That is the most believable but bizarre thing I've read today. Maybe this week. It's probably tied for the month.
It would still be >124 years from the perspective of people on Earth, though.
If you find that sort of thing interesting... I don't always know how seriously to take the things on this channel, but I discovered Fraser Cain not so long ago and find the ideas mentioned in the interviews to be fascinating, for example "Interstellar Travel Without Breaking Physics with Andrew Higgins" https://www.youtube.com/watch?v=SkGRVvA23qI (warning: it's over an hour)
JSWT... again the most formidable piece of equipment ever shot into outer space. That think is going to shake our understanding of the Universe to its foundations a couple times around
I think you mean JWST, not to be confused with JSON Web Tokens :)
:-| ugh, autocorrect. I swear!
Last time bio signatures where found (I believe on Venus), there was a flurry of papers on arXiv a week later, which all explained the signature by abiotic processes. Of course, if you have more than one explanation, then you really don't have one explanation. So I fully expect the same thing to happen here, and perhaps sometime in a decade or so follow up observations will have ruled out all but one explanation, until then exciting but ultimately it's not over before the fat lady sings.
Editorialized headline. Article is:
> Astronomers have found the 'most promising signs yet' of alien life on a planet beyond our Solar System
Every once in a while for a good chuckle I visit r/UFOs or r/aliens where people go gaga over blurry videos of balloons in the sky.
I've never understood how that stuff seems to capture the imagination more than actual science like this.
User5 on youtube.
It would be somewhat worrisome to actually find signs of primitive extraterrestrial life because of the Fermi Paradox. Given the age of the universe, and how long it took both complex life to develop on earth and for a creature such as us to emerge from that, finding life elsewhere would beg a return to Fermi's question of "Where is everyone?" implying that something comes along and causes evolving civilizations to be exterminated before they ever show signs to their presence to the wider galaxy.
If life, even of a very primitive sort, were found, it would stand to reason that it had done so in the past and that other civilizations, possibly even many of them, had formed in our huge galaxy long ago, giving them time to develop enough to be detectable even to us, so then, where are they?
Then again of course, there are probably many, many known unknowns and unknown unknowns lurking amidst all of the above supposition.
Maybe sufficiently advanced civilizations just stay under the radar to avoid being exterminated by others.
Unfortunately we cannot answer fundamental questions about ET life. Like, how long an advanced civilization lasts, which is capable of manipulating radio signals. Because we can since the last 100 years and we don't know how long we will be able.
If that time is a few hundred years, then very few happen to be functioning _now_ (in relativistic meaning) and very far away to have meaningful contact.
Here's to hoping we can learn more about this. But I feel like this could be caused by us simply not understanding how dimethyl sulfide can be formed on other planets, especially ones over 100 lightyears away..
Maybe we need to widen our search for life. Earth is a planet with about 15 degree average temperature and abundant water and oxygen. So that's what live here consumes and where it thrives. But life is all about adaptation. So, father than looking for planets with similar temperatures and resources, shouldn't we be looking for other possible foundations for life? Maybe there's a thriving civilization out there, living happily at 300 degrees, breathing neon and eating sulfur?
Is there a source for this that isn't plastered with banner ads? I can't read more than a sentence at a time without having to scroll past adverts.
I do wonder why I was stupid enough to pay for a phone with a bigger screen as it just seems to mean more and bigger ads on screen at once and the same amount of content.
Why are you not using an ad blocker? Ads are optional - I didn't see a single one.
Atmosphere of this exoplaned is rich in hydrogen. Also it has likely different atmospheric pressure than we have on Earth. Doubtful there is any life form as we know it. I suspect best we can expect there is something like a primordial soup: a mix of relatively simple organic compounds.
Aren't we looking into the past when looking at things this far away? So, just assuming here, that these are indeed signs of life, would that mean that "they" might have been primitive when these signatures were sent out into space and are now further developed?
Yes, but isn't it "just" 124 light years away. So, we're looking at it 124 years ago, which, in the scale of evolution, isn't particularly long ago?
My understanding is that the great filter theory means this is bad news for us humans here on earth. And considering the state of the world right now, it's especially ominous. Fate loves irony.
Not necessarily. I think it's reasonable to imagine that 'some sort of low-level life' might be fairly common across the galaxy ('one in a ten million'), whereas complex life - never mind 'intelligent' or technologically-sophisticated life might be very much rarer.
The older I get and the more I appreciate Just How Lucky we are to exist at all on our planet here, the more I favour the above thinking.
With due respect, the Great Filter is a hypothesis, not a theory.
That being said, I agree. I read in a similar thread yesterday someone confused how this would be bad news rather than good news—that there are many other intelligent species indicates that such a filter either doesn't exist or is very easy to pass. But, like your point does, I think it's important to recognize that such a "good news" position is predicated on the notion that we as a species are already past the Great Filter, rather than that we're still behind it and the others are ahead.
The great filter is only one of the possible explanations of the Fermi paradox however. There are other far less bleack including that there is actually no paradox at all: life is indeed frequent and but we are just bad at detecting it/have not been looking for it long enough.
I used to think that rare earth/rare life was the bleak option. As I get older, I think the bleak thing would be a galaxy full of technologically advanced species with morals potentially equal to, or worse than ours.
How so? If great filters exist at all, which is not a given, there could be multiple ones, first of all. They could be somewhere between our level of biological complexity and the kind hypothesised to be responsible for this signal. Endosymbiosis is a very plausible such filter. The evolution of language and the bootstrapping of cultural evolution is another one. Both n=1 on our planet. Probably there are others I can't think of right now.
K2-18 is a red dwarf. These stars often emit powerful flares that can "sterilise" lifeforms on nearby planets. Maybe microbial forms can protect themselves though?
Earlier discussion: https://news.ycombinator.com/item?id=43711376
Even if this has 5% of being right, it should still be upvoted all the way to the top of HN. It's that important.
How far off are we from being able to image an exoplanet?
Directly imaging an exoplanet has been done about 20 times (maybe more, by now). If you're asking how far are we from resolving an exoplanet to more than a single point of light, the answer is we will never be able to do that from this distance.
There are proposals to use the solar gravitational lens.
Failing that, you’d need thousands of optical interferometers larger than the Hubble spread across a distance wider than the Earth.
https://en.wikipedia.org/wiki/Solar_gravitational_lens
Depends on what you mean by "image". We might be able to capture blurry blobs with our current telescopes. Let's say you want to take a picture of Alien Manhattan 100 light years away, where you can see e.g. bridges and buildings, stuff about 10m across. I think we could do it pretty well if we could launch around 50,000 space telescopes, each 30 km across.
My math is below.
Note: I'm not an astronomer.
----
The angular resolution limit for a telescope is roughly the wavelength of the light it's sensitive to over the diameter.
If we want to sense things 10m across, with light at the shorter end of the visible spectrum (400 nm), we'd need a telescope with a diameter of about 1/4th of an AU (i.e. the distance from the earth to the sun), around 40 million kilometers.
More practically we could use a telescope array with this diameter, which could conveniently be in lot of orbits about 1 AU out. But the area is still a problem: assuming this 100m^2 object is as bright as it would be on earth under midday sun, it's going to be reflecting around 100 kw of energy. One of these photons has an energy of around 3 eV, so we're getting 2e23 of them a second. Unfortunately these spread out over a sphere with a surface area of 1e31 km^2 by the time they reach earth, meaning we see one every second if we have a telescope array with an area of 50 million square km.
Ok, so let's go kind of sci-fi and say we can build a 30 km diameter space telescope. It would be impressive (and unprecedented) but since it's floating in space and could be made of thin material you might be able to imagine it with today's technology and a lot of coordination. That gets us around 1000 square km! Now we just do it 50,000 more times.
Great, now we have 1 Hz of photons coming from each 100 m^2 patch of Alien Manhattan! I'm sure in the process of building 50k mega-projects we'll figure out a way to filter out the noise, and with a few years of integration we'll have a nice snapshot!
Most signs promise that life is to become alien on our planet.
The ads on that website are horrible, constantly shifting the text as they load. Don't recommend clicking on it.
Time to (re)read "Where is everybody?" [1]
[1] https://www.goodreads.com/book/show/180506.If_the_Universe_I...
So 355% tariff then? Say what?
This is very exciting. It's certainly approaching the best evidence we could possibly hope for from an exoplanet given current technology.
Of course, the weak link here is the assumption that these bio-markers can't be produced abiotically, which is a pretty big assumption. Our understanding of planetary science is still in its infancy. This is (thought to be) a hycean planet, a type of planet unknown to us until very recently(post-JWST, I believe?). And given that the solar system has no hycean planets, it's a class of planets which is fundamentally poorly studied, with pretty limited access to data. We can make models, and we can get some spectral data on the contents of their gaseous atmospheres. But we have no way of looking at their surface oceans. Thinking about what kind of chemistry might be going on there is mostly just an act of speculative modelling.
So the interesting question is, without new sources of data, can we determine whether these bio-markers are biological in origin? Not really. Not without a much better understanding of planetary science in general and hycean worlds in particular(of course, that's what this research is trying to do, and making progress at). As well as a deeper understanding of abiogenesis. I could imagine a working understanding of abiogenesis at least being able to eliminate some candidate planets, but even that assumes only one type of abiogenesis is possible, which is more or less unfounded. That is, unless the understanding includes some deep information theoretic/evolutionary perspective on abiogenesis which would probably have to include a completely unambiguous information theoretic and physical definition of what life even is. It is conceivable that such an understanding might provide very strong restrictions on what kinds of chemical systems are capable of abiogenesis, and that those restrictions could then be used to eliminate certain planets or even entire star systems from contention. And if these hycean worlds were eliminated that way, we'd know there must be some abiotic source of these "biomarkers", and knowing that, we would likely be able to figure out what it is. But ok, that's a lot of assumptions.
Maybe we get lucky, and some chemists stumble on a non-biotic chemical system that can produce these chmicals in concentrations that can be detected by JWST at a distance of hundreds of light years. Or, conversely, maybe chemists somehow manage to prove conclusively that biotic origin is the only possible source. I'm not a chemist or a microbiologist, so I have no idea what that would look like. It's probably well beyond our current understanding.
I guess what I'm rantingly saying is, while this result changes my credence that there's life on this planet about as much as is possible with current science and technology, it still barely changes it at all. Before it was maybe 0.5 + ε(habitable zone, liquid water), and it is now 0.5 + 2ε.
I guess something which could move the needle much more significantly, is if we found a large number(say 10) of chemically unrelated potential bio-markers in the atmosphere of a planet very similar to earth, in a very similar star system. Then, the assumption of the impossibility of abiotic sources would be much more plausible. I believe doing this type of research for earth-sized exoplanets with JWST is still quite borderline(please correct me if I'm wrong).
Having said all that, this result is still extremely exciting. For the first time, the field of exobiology has any contact with observational data from outside our solar system at all(besides mere astronomical data), and things will only improve from here. Future telescopes will be better at this type of observation, and our understanding of planetary science is evolving at an accelerating pace. I'm very excited to see where this research goes in the future.
Molecule of beer, mmm...
"Science, turning existential questions like 'Are we alone in the Universe ?' into 'Did something just fart over there ?' since 500 years".
This is a terrible title. The original title was: "Astronomers have found the 'most promising signs yet' of alien life on a planet beyond our Solar System"
"Astronomers have found signs of alien life on a planet beyond our Solar System" means something completely different. Please @dang update or this looks like the Daily Mail.
It's an example of scientists acting irresponsibly. They might have found dimethyl sulfide but it can be produced abiotically.
Dimethyl sulfide (CH3SCH3, DMS) signatures were found in comet 67P/Churyumov-Gerasimenko and that is for sure not Times Square on Saturday night...: https://astrobiology.com/2025/02/on-the-abiotic-origin-of-di...
The planet looks more like a Neptune or Uranus than Earth type. They need to find multiple examples of different types of biomarkers, before contacting the press as they obviously did.
"Evidence for Abiotic Dimethyl Sulfide in Cometary Matter" - https://arxiv.org/abs/2410.08724
"On the abiotic origin of dimethyl sulfide: discovery of DMS in the Interstellar Medium" - https://arxiv.org/abs/2501.08892
Edit: I see title is now updated.
Signs of alien life existing at least 124 years ago? Or are these types of observations exempt from the distance delay?
Maybe now we can stop this nonsense of competing among each other and start dedicating efforts to an international space program.
Why exactly? I'd prefer we'd just build some more houses so that owning one didn't require a life time of work to pay for.
Housing prices have almost nothing to do with space programs. In most places, they’re an artifact of laws and policies which create scarcity for the benefit of rich property owners, and cutting scientific research entirely won’t change that except in a few cases where you’d be able to bid on a house which some unemployed scientist or engineer is forced out of - but the private equity guys will probably outbid you.
[flagged]
I truly agree with this post.
There was this post on HN that life can't be given to mars for 99.99% and even if it could, it would be the most miserable life with only 1-2 decades. It isn't self sustainable as people imagine it to be.
So all we have is, is this Earth & our fellow human beings & instead of treating each other with basic necessities like housing, education , healthcare.
Also these things, in my opinion of researching the space and giving housing, they aren't mutual. They can both be done but even if they are mutual,I would personally pick housing any day, because what point is of space, what point is of going to outer space some day and living shit there if humans are currently living shit here as well.
Regarding Housing, I think it can easily be fixed and so much more like how we say tax the rich, if we could just tax lands.
Because people think of land as some "asset" and that they "own it" ,when in actuality, I might argue that land is the only thing that I personally think the govt. has any right over. So I personally believe that we are better off taxing land so that these pesty landlords who get rich off of the housing crisis can really just suffer so much that the lands would just be productive and not speculative , reducing the price of lands down and even rents down till the point housing is way more favourable.
Its a net win to everybody except those pesty landlords & maybe "investors" or people who bought housing pre-georgism because they might now believe that its unfair to them? Still I think that georgism is pretty flexible and this could be sorted out in such a way that it would have been less controversial and more net positive to the Society than the latest tariffs fiasco, though people didn't vote for housing, they voted for tariffs.
Maybe let's just try to stop genocide happening here first and try not send innocents people to prisons in el Salvador.
That literally smells fishy
Astronomers have yet again found possible signs of alien life.
You're not thinking like a journalist. This is a breakthrough! Alien life has been found! SETI is making contact as we speak.
To be fair, there’s a big difference between journalists and headline writers!
Headline writing is the art of taking something that a journalist has thought about in detail and carefully crafted and making it into something that someone with low to zero interest in the topic might want to read.
Having done both, I got annoyed when headlines misrepresented what I’d written, and journalists got annoyed when I took their perfectly crafted but pedestrian articles and gave them punchy headlines in a desperate attempt to get people to read them...
Fair enough! Also, to the credit of headline writers, I have sometimes clicked on a clickbait article and learned something. If it hadn't been clickbait, I might have missed it.
You've made all headline writers a little happier by saying that!
TL;DR
- K2-18b
- detected dimethyl sulfide and dimethyl disulfide, false positive possibility is now very low
- "produced by marine-dwelling organisms on Earth", possibility they were produced by other processes (unrelated to life as we know it) not high but maybe unknown unknowns
- other factors like distance from the star are in favor of life & water
- previous studies detected methane and carbon dioxide
> false positive possibility is now very low
It's not that low, unfortunately. From the article:
> They say their observations have reached the ‘three-sigma’ level of statistical significance. This means there's a 0.3% probability the detection occurred by chance. And to reach the accepted level that would mean scientific discovery, observations would have to meet the five-sigma threshold. In other words, there would need to be below a 0.00006% probability they occurred by chance.
Thats what I'd like to know, is this the kind of process that we can _get_ to 6 sigma by more observation time? Or would we need other observations / thats "as good as it gets" for the Webb's capabilities?
> false positive possibility is very low
No, it means we will soon discover how these compounds form naturally. Would love to be wrong, of course.
I meant (and I think the article meant) false positive of gas detection not life
Maybe the are cooking a lot of paper over there. https://en.wikipedia.org/wiki/Kraft_process
If plankton farts them, it's natural too, right?
> The observations also provided a tentative hint of dimethyl sulfide (DMS), a possible biosignature gas, but the inference was of low statistical significance.
From the source paper. It is a very important result but not definitive, false positive is still possible as well as us finding a new way in which DMS can form without a biological process.
Still freaking exciting and fantastic scientific achievement. JWST is already bearing incredible fruits.
Is dimethil something expected to be generated with really procaryote life forms, or only from those with more complexe structures?
Parent is a flare star
Like the sun, I guess
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You are dismissing a lot of science off-hand by trivializing it snidely. Exactly which part do you think is wrong?
a fart/sewer odor is indeed a sign of life
Oh please, it's a detection of dimethyl sulfide on a planet far far away whose natural chemistry we don't understand.
Morons, I'm surrounded by morons.
Let’s assume there is alien life on many planets beyond our solar system. Now what? What’s the practical benefit?
Suppose it were somehow possible to prove that alien life exists. Like, we get a radio signal saying "hey, Earth! We see you looking at us!" that's conclusive and undeniable.
That would upend a lot of religious teachings which say we're unique and that the world was given to us, as the unique creations of a creator, to consume for our own benefit.
It seems like there could be many practical benefits to showing that's not true. Hey, maybe the concept of infinite exponential growth is a bad idea. Maybe we shouldn't burn the skies and boil the seas. Maybe we should be nice to other intelligent animals, at the very least.
What's the practical benefit of Beethoven?
Beethoven’s music directly impacts human lives. It evokes emotion and inspires creativity. Its value lies in its immediate effect. In contrast, knowing that life exists millions of light-years away offers no such tangible impact. It’s a data point. An interesting one, sure, but it doesn’t feed the hungry, cure disease, change policy, or even affect your commute. So yea, Beethoven is a lived experience, whereas aliens in Andromeda are an abstract concept.
Let's assume I wake up tomorrow still alive. Then what? You're basically asking what's the meaning of life.
If you wake up tomorrow still alive, you can visit HN and downvote my comments. That will impact my karma value. Not a big deal, but still. If there is alien life, you can’t do anything about it. Zero impact.
124 light years seems quite close, it seems to be some sort phytoplankton for now, what can we send there quickly to eradicate them before they become a problem. How much mass of galactic "roundup" should we send ? Do we have the technology yet for planet-scale sanitizing ? Can we pulse some high energy particles at roughly the speed of light and aim it at them ? Do we know if they have some magnetic field protection like earth does ?