Posted by fuidani 2 days ago
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.
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.
That’s quite a different tone from the article, and I think the comments here and elsewhere online reflect that.
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..."
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.
edit: Any chance someone might have the charity to explain why my criticism is so far off-base, according to the HN consensus?
- 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
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.
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.
(if you want a cleaner interface)
https://en.wikipedia.org/wiki/Dimethyl_sulfide#Industrial_pr...
Which part requires a living organism?
For a non-life explanation, you're really looking for something that could plausibly happen in (abiotic) nature, not an industrial process.
Which part requires a living organism?
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, on the other hand, life is relatively rare, or we're the sole example, our future can't be statistically estimated that way.
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.
[0] https://www.quantamagazine.org/intelligence-evolved-at-least...
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.
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.
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.
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?
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.
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.
Based on what evidence? We only know if it happening once, after a very long delay.
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.
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?
I wonder if things would progress if they had the same level of communication that dolphins do.
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.
I can't think of any plausible ways a water-bound species would be able to harness and use electricity either
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.
(warning, this is one of the most depressive pages on Wikipedia)
[0]: https://en.wikipedia.org/wiki/Timeline_of_the_far_future
[1] https://en.m.wikipedia.org/wiki/Star_lifting [2] https://www.orionsarm.com/eg-article/4a48d58c84350
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.
If we are able to harvest the solar system resources it would take by then.
Trial run for the bigger “solar warming” event.
In 500 million years absolutely anything could happen (if we survive this century).
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.
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.
Your anti-science bot comment however, is very anti-science.
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"
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.
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.
[1] https://pmc.ncbi.nlm.nih.gov/articles/PMC4494450/
If you're referring to technology/civilization-building capabilities, that is a different matter.
The Sun will not become a red giant in 500 million years.
Life might be very common, but intelligent life still be incrediblY rare.
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.
Another 34% is Forrest, much of which is managed for logging.
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...
There were geological events and asteroid impacts that may result in more dramatic changes, but their signatures will be different.
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.
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.
https://galileo.phys.virginia.edu/classes/109.jvn.spring00/n...
That bridge is also within our technological capacity. But it’s not happening period.
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.
https://ia800108.us.archive.org/view_archive.php?archive=/24...
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.
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.
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.
The Trisolarians developed FTL travel while they were on the way to Earth, IIRC.
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.
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...
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.
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.
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.
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 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.
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.
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.
Besides, lack of comical presence doesn’t necessarily mean demise: maybe all face the problematic consequences of uncontrolled industrialisation and go solar punk?
> And the absence of those signs would be relatively strong evidence that life, while common, isn't long-lived.
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.
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.
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.
Maybe people just don't _actually_ build that many megastructures.
[0] Terminology from Dan Simmons's Hyperion. Would also recommend Joe Haldeman's The Forever War for more time dilation themes.
When you think of it, light speed is really slow. Even on Earth we are capped by it.
How come we’re making progress on this without a 1bn km telescope?
https://arxiv.org/abs/1802.08421
...and someone made an awesome video about it:
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.
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.
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.
That is, if there is supposedly one civilisation with clear advance in technology, it could just as well be humanity.
> 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?
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.
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.
Unless faster than light travel or communication becomes avaliable, it might not even make sense to travel through the galaxy.
> 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.
If dark forest theory is right, alien civilizations may stay undetectable by hiding biological signatures of their worlds.
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
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.
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.
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 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.
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.
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."
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.
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?
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.
What a bizarre thing to say, considering this very discovery leans on decades of science and engineering over the past 50 years!
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
> [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.
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.
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.
Not millions, not even billions. 124 light years is about 10¹⁵ kilometers, or a million billion kilometers.
But the probability of developing a highly developed civilization can be much, much smaller than 1 / number of planets in the universe.
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).
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.
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.
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!
Erk. Couldn't you pick something from a less... apocalyptic universe? :)
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..."
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/...
- 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
> 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.
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.
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.
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.
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.
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.
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.
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 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
> Astronomers have found the 'most promising signs yet' of alien life on a planet beyond our Solar System
I've never understood how that stuff seems to capture the imagination more than actual science like this.
"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.