Life on Earth and elsewhere

[BaalChatzaf]

This is a very  good and informative  show of how we can determine if there is life on other planets.

Please do see:  

 

[jts]

All species of life on planet Earth probably have a common ancestor if you go back far enough. Any native life on an alien planet would be unrelated to anything native to Earth. Given a grasshopper and a mushroom and a banana and a dog and a tomato and a frog and a spider, all of them have a lot of DNA in common. An alien life form would have probably no DNA in common and maybe no DNA. You would have more in common with a spruce tree than with the alien. It would not be like Star Trek where most of them are humanoid and most of them speak English. They probably would be stranger than any science fiction writer can imagine.

We know perhaps only one thing for sure. Any native life form on an alien planet would be adapted to survive conditions on the planet.

 

[BaalChatzaf]

The same kind of distant observation than can "prove" life exists on Earth,  can also be used to see if life exists on distant extra solar  earth-like planets.  The main clue is liquid water.

[Brant Gaede]

50 minutes ago, BaalChatzaf said:

The same kind of distant observation than can "prove" life exists on Earth,  can also be used to see if life exists on distant extra solar  earth-like planets.  The main clue is liquid water.

Oh, life is probably everywhere. Complex life is more problematic. Cognitively intelligent life that builds civilizations? Not likely--not in this galaxy. (And DNA doesn't need much intelligence to get reproduced). This was spelled out in the book Rare Earth. This is a unique planet because of its likely unique moon. You can have many earth like planets a right difference from the right sized sun. Good luck finding one with a large stabilizing moon.

(It's awfully queer that the moon is just the right size for a total solar eclipse. [Or is it bigger than necessary?])

--Brant

[BaalChatzaf]

13 minutes ago, Brant Gaede said:

Oh, life is probably everywhere. Complex life is more problematic. Cognitively intelligent life that builds civilizations? Not likely--not in this galaxy. (And DNA doesn't need much intelligence to get reproduced). This was spelled out in the book Rare Earth. This is a unique planet because of its likely unique moon. You can have many earth like planets a right difference from the right sized sun. Good luck finding one with a large stabilizing moon.

(It's awfully queer that the moon is just the right size for a total solar eclipse. [Or is it bigger than necessary?])

--Brant

In places without liquid water any life there would not be like any we know on earth.  The video explains why liquid water is crucial  to life. 

[Peter]

On ‎8‎/‎24‎/‎2017 at 10:24 PM, BaalChatzaf said:

In places without liquid water any life there would not be like any we know on earth.  The video explains why liquid water is crucial  to life. 

Methane, liquid water, the existence of a planet in a habitable orbit with similar planetary temperatures to earth, and nitrous oxide on an oxygen rich planet, could indicate life. Those features are indicative of chemical reactions other than simple geologic reactions.

I gathered from the video, that as early as in 2018 or at least in our lifetimes we will know if we are alone in the universe. Wow!

[BaalChatzaf]

1 hour ago, Peter said:

Methane, liquid water, the existence of a planet in a habitable orbit with similar planetary temperatures to earth, and nitrous oxide on an oxygen rich planet, could indicate life. Those features are indicative of chemical reactions other than simple geologic reactions.

I gathered from the video, that as early as in 2018 or at least in our lifetimes we will know if we are alone in the universe. Wow!

The best we could  get is data showing one or more rocky planets in the "goldilocks"  zone with atmospheric indications that the planet COULD support life.   Short of getting a definite message (like the sequence of prime integers) or a visit from sentient aliens we will not know for sure if we are alone.