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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

#51

Post by ivan_gammel »

martopix wrote: post #47
aardvark179 wrote: post #27

Earlier quoted context omitted.

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

We are capable of rapidly changing chemical composition of atmosphere, which may be noticeable even at our technological level.

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

#52

Post by fy20 »

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…

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.

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

#53

Post by poulpy123 »

allan_s wrote: post #33
metalman wrote: post #19

Earlier quoted context omitted.

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…

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

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

#54

Post by IsTom »

dtech wrote: post #44
Andrew_nenakhov wrote: post #40

Earlier quoted context omitted.

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 sun has about 5B years more to go before it turns into a red giant, not 0.5B 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.

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

#56

Post by ivan_gammel »

dtech wrote: post #44
Andrew_nenakhov wrote: post #40

Earlier quoted context omitted.

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 sun has about 5B years more to go before it turns into a red giant, not 0.5B years...

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.

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

#57

Post by milesrout »

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.

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

#58

Post by DiogenesKynikos »

IsTom wrote: post #54
dtech wrote: post #44

Earlier quoted context omitted.

The sun has about 5B years more to go before it turns into a red giant, not 0.5B 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.

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.

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

#59

Post by meindnoch »

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…

>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.

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