Is there life in the Universe?

[Dryson]

After reading this short cut from a Wiki Article I am a firm believer that life other than humanoid exists in the Universe

The pessimists' most telling argument in the SETI debate stems not from theory or conjecture but from an actual observation: the lack of extraterrestrial contact.[3] A civilization lasting for tens of millions of years would have plenty of time to travel anywhere in the galaxy, even at the slow speeds foreseeable with our own kind of technology. Furthermore, no confirmed signs of intelligence elsewhere have been spotted, either in our galaxy or the more than 80 billion other galaxies of the observable universe

More than 80 billion galaxies. How many solar systems does each galaxy have? How many planets in each solar system.

Using a modest number of a one trillion total planets minus suns and then dividing 1 trill by .01% we still have 10,000,000,000 (10 billion) possible planets in our Universe that are inhabitable.

There is a lot of hope in that little .01%.

 

[thestrangequark]

You can't extrapolate from a single data point. We know of one instance of life in the universe, that's it. Rationally, you can't say there is or isn't, or even venture a probability.

That being said, my gut says, "There must be...and lots!" and the romantic in me is the reason for the framed copy of the Drake equation on my bookshelf.

 

[sojourner]

As the quote from Contact goes, "If there isn't life out there, seems like an awful waste of space". - To paraphrase, I can't be bothered to lookup the exact quote.

 

[RoJoHen]

Using a modest number of a one trillion total planets minus suns and then dividing 1 trill by .01% we still have 10,000,000,000 (10 billion) possible planets in our Universe that are inhabitable.

There is a lot of hope in that little .01%.

You can't just pull statistics out of thin air like that.

While my gut tells me that there is probably life out there, the math just doesn't support it yet.

 

[scotthm]

There is a lot of hope in that little .01%.

Hope for what, that microbial life exists on an average of one planet per eight galaxies?

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[Taylirious]

Earth is a happy miracle. Yay!

 

[Spider]

I'd be surprised to find we are the only examples of life in the universe. The only problem is we still don't know how it emerges from non living material, and even if we did, it would be the process that worked in our ancient biosphere. If the process of evolving from non living material into living material happens in a much different ecosphere, would we even have the ability to recognize it as life unless it's obviously advanced? Very primitive life in an alien biosphere could very easily be mistaken for natural chemical processes.

 

[gturner]

I should probably fess up to creating life on Earth when I wasn't paying attention to what I was doing and knocked over the Beaker that should Never be knocked over. In my haste to cover up the mistake, I flushed the spill into the ships drain system which had a port that dumped trash into the yawning gulf above the roiling oceans of a young, unstable planet. That kind of thing almost never happens, and I wouldn't be surprised if my screw up was as unique as it was embarrassing.

 

[Silvercrest]

You fool! Don't you realize what you've done?

 

[SPCTRE]

I'd be surprised to find we are the only examples of life in the universe.

I'd be surprised to find that we are the only examples of life in our solar system.

 

[YellowSubmarine]

As the quote from Contact goes, "If there isn't life out there, seems like an awful waste of space". - To paraphrase, I can't be bothered to lookup the exact quote.

If there isn't life out there, the space isn't exactly wasted, it was the right amount of breeding ground that was necessary for us to appear. And if we manage to get extinct quickly, well, that's one good use of all the space that was allotted to us.

You can't extrapolate from a single data point.

You can't, but it isn't exactly a single point. Emergence of multicellular life happened more than once on Earth, sexual reproduction evolved more than once, appearance of limbs happened more than once. So you have more than one point, and you can assume these are likely. If we manage to reproduce abiogenesis, we'd have more than one data point on the critical steps for complex life and we'd know there is life out there.

Unfortunately, all brains come from a common ancestor, so we won't know if other organisms in the universe would have brains.

 

[sojourner]

As the quote from Contact goes, "If there isn't life out there, seems like an awful waste of space". - To paraphrase, I can't be bothered to lookup the exact quote.

If there isn't life out there, the space isn't exactly wasted, it was the right amount of breeding ground that was necessary for us to appear. And if we manage to get extinct quickly, well, that's one good use of all the space that was allotted to us.

That sounds like an even bigger waste.

 

[RoJoHen]

You can't extrapolate from a single data point.

You can't, but it isn't exactly a single point. Emergence of multicellular life happened more than once on Earth,

The key phrase being "on Earth." For all we know, Earth is literally the only planet in the entire universe with the right conditions for these things to occur.

So yes, it's still just a single data point in the context of interstellar life.

 

[scotthm]

Very primitive life in an alien biosphere could very easily be mistaken for natural chemical processes.

Are you suggesting that life is not a natural chemical process?

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[Spider]

Very primitive life in an alien biosphere could very easily be mistaken for natural chemical processes.

Are you suggesting that life is not a natural chemical process?

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No, I'm suggesting any truly alien life may find another means of encoding its properties in something other than RNA/DNA before passing it along to its progeny. Our definition of "life" may have to expand. Unless this life is obviously observed "doing something" that rocks and soils can't, it might be difficult to distinguish the living and non-living in an alien environment, most especially if it's very primitive.

 

[Kemaiku]

You can't extrapolate from a single data point.

You can't, but it isn't exactly a single point. Emergence of multicellular life happened more than once on Earth,

The key phrase being "on Earth." For all we know, Earth is literally the only planet in the entire universe with the right conditions for these things to occur.

So yes, it's still just a single data point in the context of interstellar life.

Exactly, even if it happened twice, it happened in the same ecosystem/closed-system containing those building blocks.

Those conditions and essential chemical building blocks are not guaranted anywhere other than Earth.

 

[Spider]

I'd be surprised to find we are the only examples of life in the universe.

I'd be surprised to find that we are the only examples of life in our solar system.

If life can arise spontaneously as quickly as it did on Earth, there is no reason that it shouldn't have done that on early Mars. I believe there is still microbial life on Mars underground, but if there isn't, I think we'll find it's fossilized remains.

 

[YellowSubmarine]

Exactly, even if it happened twice, it happened in the same ecosystem/closed-system containing those building blocks.

Those conditions and essential chemical building blocks are not guaranted anywhere other than Earth.

And there could have been a genetic trait found by chance in our common ancestor that facilitates the emergence of multicellular forms. Say, maybe life elsewhere in the universe utilises less complex DNA and genetic mechanisms, and that means no multicellular organisms.

Which is why reproducing and understanding the beginning of life and its requirements is a prerequisite for making more serious assumptions. You'll know more about the limits on the environment and the nature of the life that would emerge.

(That doesn't mean that those processes happening multiple times doesn't have an effect on the probability of life elsewhere. You do have more data points, you just don't know how correlated they are. If they are strongly correlated, it's the same as if you had one, but you do have the real possibility that they are correlated loosely or not at all, in which case they mean an awful lot. Such information adds up, and you could potentially learn enough from Earth's life to make conclusions about life elsewhere in the universe – it's just that we aren't close to such a point.)

 

[Haggis and tatties]

I hope so.

 

[Asbo Zaprudder]

Time for a song:

[yt]http://www.youtube.com/watch?v=dWBmaKk32fE[/yt]