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Life on other planets would likely be brief and become extinct very quickly

astronomy.com

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Re: Life on other planets would likely be brief and become extinct very quickly

#21

Post by ceejayoz »

orf wrote: post #10

People always talk about how vast space is, but rarely about how vast time is. We've been looking for life for the last what, 60 years or so? It seems like not only is space so vast which makes finding evidence of life hard, but this is made even harder by the small volume of time we are likely to be around to try and observe in the grand scheme of things. Alien life has to be relatively close in terms of distance as…

> Would we be around to see it?

And how long does an average civilization broadcast radio?

On the "life is safe" end of the spectrum, maybe there's much better technology to be discovered. On the "life is dangerous" end, maybe you learn pretty fast not to broadcast your location to the galaxy.

Re: Life on other planets would likely be brief and become extinct very quickly

#23

Post by givan »

I wonder why on this subject everyone overlooks two major events witnessed by thousands of people some of which former military pilots and instead focus on science fiction scenarios.

https://en.wikipedia.org/wiki/Belgian_UFO_wave

https://en.wikipedia.org/wiki/Phoenix_Lights

People try to explain these events in all kind of ways avoiding the most obvious one no matter what.

Is it fear? the lack of recognition by authorities? I never understood why people will talk freely about aliens in the universe but aliens here is always a taboo or a subject of ridicule no matter the evidence.

Re: Life on other planets would likely be brief and become extinct very quickly

#24

Post by PuffinBlue »

Florin_Andrei wrote: post #20
civilian wrote: post #7

I've been reading The Vital Question by Nick Lane, where he puts forth some theories about the origin of eukaryotes, and life in general. It does make it seem that abiogenesis and eukaryote-genesis are much more difficult than we give them credit for. So in the Drake Equation, I think that F[L] is probably pretty low. And because eukaroyte genesis is difficult and only happened once (and it took a billion years of ba…

One thing to keep in mind is that the time interval of stability for Earth as a life-bearing planet is actually fairly close to the end. We're past the 75% point. The Sun's evolution will "soon" put an end to that (speaking on a cosmic scale). So it seems like it was a close call. Life needed almost the full extent of that interval of stability to create an (arguably) intelligent species. There can be no reset and st…

"How long do you say the sun had left?"

"...5 billion years."

"Whew, that's OK, I though you said 5 million!"

Re: Life on other planets would likely be brief and become extinct very quickly

#25

Post by Florin_Andrei »

reasonattlm wrote: post #18

No answer to the Fermi Paradox works if it requires all aliens to uniformly come to the same end state or satisfy some boundary condition without exception. All it takes is the one exception, one small group in one suitably advanced civilization, and you have self-replicating probes building an expanding wave of computronium, dismantling even the stars themselves as soon as the economics favor a better use for that m…

> dismantling even the stars themselves

It's unclear whether that's actually feasible from an energy balance perspective. You'll need a lot of energy to re-arrange things on that scale. Each star is already sitting at the bottom of its own local energy well.

Maybe the far future will discover radically new ways to produce energy - but until then, this whole thing about the wave of computronium flooding the universe is pure speculation.

Re: Life on other planets would likely be brief and become extinct very quickly

#27

Post by putlake »

Liu Cixin's The Dark Forest, the second book in his 3-body problem trilogy, posits a similar philosophy: resources are limited so civilizations annihilate other civilizations. So if an alien civilization knew about earthlings, they will destroy earth ASAP if they are capable, lest the earthlings come after their resources.

This is also why some people believe we should not try to make contact with intelligent alien life. They believe broadcasting our location is dangerous.

Re: Life on other planets would likely be brief and become extinct very quickly

#28

Post by Florin_Andrei »

PuffinBlue wrote: post #24
Florin_Andrei wrote: post #20

Earlier quoted context omitted.

One thing to keep in mind is that the time interval of stability for Earth as a life-bearing planet is actually fairly close to the end. We're past the 75% point. The Sun's evolution will "soon" put an end to that (speaking on a cosmic scale). So it seems like it was a close call. Life needed almost the full extent of that interval of stability to create an (arguably) intelligent species. There can be no reset and st…

"How long do you say the sun had left?" "...5 billion years." "Whew, that's OK, I though you said 5 million!"

> 5 billion years

The Sun will get significantly hotter over the next 1 billion years. Life on Earth will become impossible (unless artificially maintained) quite a while before the end of that 1 billion year interval.

Re: Life on other planets would likely be brief and become extinct very quickly

#30

Post by Animats »

Industrial civilization may not last very long. Industrial civilization on Earth is only about 200 years old. A useful starting point is the first time a railroad train carried paying passengers. There were earlier demos and prototypes, but think of that as the moment the Industrial Revolution got out of beta. Progress up to then was very slow. Progress after that was very fast.

About 75 years ago, progress reached the point that a substantial dent could be made in the planet's resources. Until then, human activity just wasn't large scale enough. Now, we can see the end in sight for many resources. On a scale of centuries, most mineral resources run out.

The high-power, heavy industry phase of life may have an expiration date that's closer in time than the founding of Oxford University.

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