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

skyatnightmagazine.com

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

#121

Post by dotancohen »

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…

  > 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.

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

#122

Post by ImHereToVote »

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…

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.

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

#123

Post by ivan_gammel »

milesrout wrote: post #66
ivan_gammel wrote: post #49

Earlier quoted context omitted.

> 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.

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…

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.

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

#125

Post by autonomousErwin »

cedilla wrote: post #73
ivan_gammel wrote: post #49

Earlier quoted context omitted.

> 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.

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

#126

Post by fullstackchris »

davedx wrote: post #68
meindnoch wrote: post #59

Earlier quoted context omitted.

>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 f…

> 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!

Many trolls hiding in these comments... either that or they just dont understand what the scientific method is.

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

#127

Post by rsynnott »

ta8645 wrote: post #45
Philip-J-Fry wrote: post #34

Earlier quoted context omitted.

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.

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.

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

#128

Post by rsynnott »

cedilla wrote: post #73
ivan_gammel wrote: post #49

Earlier quoted context omitted.

> 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

Of course, the risk is, thinking that centuries is a long time may be merely a human, and not a universal, trait.

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

#129

Post by mr_mitm »

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

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.

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

#130

Post by joseppu »

Intralexical wrote: post #117
goognighz wrote: post #86

Earlier quoted context omitted.

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.

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.
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