“Most promising signs yet” of alien life on a planet beyond our Solar System • Hacker News Board

Re: “Most promising signs yet” of alien life on a planet beyond our Solar System

#131

Post by rsynnott » Thu, Apr 17, 2025, 10:43 AM UTC

davedx wrote: post #92

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, es…

> 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? :)

Re: “Most promising signs yet” of alien life on a planet beyond our Solar System

#132

Post by Imustaskforhelp » Thu, Apr 17, 2025, 10:44 AM UTC

Scarblac wrote: post #81

ta8645 wrote: post #18

Earlier quoted context omitted.

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 t…

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.

Re: “Most promising signs yet” of alien life on a planet beyond our Solar System

#133

Post by simiones » Thu, Apr 17, 2025, 10:44 AM UTC

ta8645 wrote: post #72

mnky9800n wrote: post #28

Earlier quoted context omitted.

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.

Re: “Most promising signs yet” of alien life on a planet beyond our Solar System

#134

Post by rsynnott » Thu, Apr 17, 2025, 10:44 AM UTC

xrisk wrote: post #76

poulpy123 wrote: post #53

Earlier quoted context omitted.

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?

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.

Re: “Most promising signs yet” of alien life on a planet beyond our Solar System

#135

Post by ninetyninenine » Thu, Apr 17, 2025, 10:45 AM UTC

seanhunter wrote: post #6

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 d…

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.

Re: “Most promising signs yet” of alien life on a planet beyond our Solar System

#136

Post by [deleted] » Thu, Apr 17, 2025, 10:45 AM UTC

Andrew_nenakhov wrote: post #40

ta8645 wrote: post #18

Earlier quoted context omitted.

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 t…

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 eme…

[deleted]

Re: “Most promising signs yet” of alien life on a planet beyond our Solar System

#137

Post by rsynnott » Thu, Apr 17, 2025, 10:46 AM UTC

hidroto wrote: post #106

mr_mitm wrote: post #75

Earlier quoted context omitted.

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…

It does not have to be a chemical rocket. https://en.wikipedia.org/wiki/Breakthrough_Starshot

While still ludicrously optimistic, there's a vast gulf between "20% the speed of light" and "constant 1g acceleration for 10 years", energy-wise.

Re: “Most promising signs yet” of alien life on a planet beyond our Solar System

#138

Post by fullstackchris » Thu, Apr 17, 2025, 10:47 AM UTC

energy123 wrote: post #15

throwaway290 wrote: post #2

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…

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?

Re: “Most promising signs yet” of alien life on a planet beyond our Solar System

#139

Post by uwagar » Thu, Apr 17, 2025, 10:47 AM UTC

Andrew_nenakhov wrote: post #40

ta8645 wrote: post #18

Earlier quoted context omitted.

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 t…

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 eme…

why isnt a crocodile sentient?

Re: “Most promising signs yet” of alien life on a planet beyond our Solar System

#140

Post by voidUpdate » Thu, Apr 17, 2025, 10:49 AM UTC

ta8645 wrote: post #18

seanhunter wrote: post #6

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 d…

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 t…

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