Approx. 1st time life could appear in universe?

[mistermack]

I think that the critical question is how long after the seas stopped boiling did life appear?
It's liquid water at a reasonable temperature that's needed, and the evidence is that life appeared quite quickly once the seas cooled.
If it had taken billions of years for the seas to cool, it's likely that life would have only just got going.

[Gawdzilla Sama]

I think that the critical question is how long after the seas stopped boiling did life appear?
It's liquid water at a reasonable temperature that's needed, and the evidence is that life appeared quite quickly once the seas cooled.
If it had taken billions of years for the seas to cool, it's likely that life would have only just got going.

Ever seen the conditions around the black smokers? Near boiling temps and life is going crazy. This tempts me to think that they are the source of life on this planet.

[mistermack]

I think that the critical question is how long after the seas stopped boiling did life appear?
It's liquid water at a reasonable temperature that's needed, and the evidence is that life appeared quite quickly once the seas cooled.
If it had taken billions of years for the seas to cool, it's likely that life would have only just got going.

Ever seen the conditions around the black smokers? Near boiling temps and life is going crazy. This tempts me to think that they are the source of life on this planet.

I know what you mean, that is widely suggested, and it might be right.
But I have a feeling that it's the other way round, and that life evolved first, and then evolved ways of coping with the high temperatures.
I've got no evidence to back that up, just a feeling that life would need to be highly specialised to survive high temperatures, and would need millions of years to evolve that ability.

That's just a hunch though, and it might be completely wrong.

[Gawdzilla Sama]

I think that the critical question is how long after the seas stopped boiling did life appear?
It's liquid water at a reasonable temperature that's needed, and the evidence is that life appeared quite quickly once the seas cooled.
If it had taken billions of years for the seas to cool, it's likely that life would have only just got going.

Ever seen the conditions around the black smokers? Near boiling temps and life is going crazy. This tempts me to think that they are the source of life on this planet.

I know what you mean, that is widely suggested, and it might be right.
But I have a feeling that it's the other way round, and that life evolved first, and then evolved ways of coping with the high temperatures.
I've got no evidence to back that up, just a feeling that life would need to be highly specialised to survive high temperatures, and would need millions of years to evolve that ability.

That's just a hunch though, and it might be completely wrong.

I favor the other direction. The hot water, high mineral content, and the RNA that may have been delivered by comets would have a nice witch's brew for life to start in.

I'll have to ask Pensioner if he remembers it one way or the other.

[Mr P]

I think that the critical question is how long after the seas stopped boiling did life appear?
It's liquid water at a reasonable temperature that's needed, and the evidence is that life appeared quite quickly once the seas cooled.
If it had taken billions of years for the seas to cool, it's likely that life would have only just got going.

Ever seen the conditions around the black smokers? Near boiling temps and life is going crazy. This tempts me to think that they are the source of life on this planet.

I know what you mean, that is widely suggested, and it might be right.
But I have a feeling that it's the other way round, and that life evolved first, and then evolved ways of coping with the high temperatures.
I've got no evidence to back that up, just a feeling that life would need to be highly specialised to survive high temperatures, and would need millions of years to evolve that ability.

That's just a hunch though, and it might be completely wrong.

I favor the other direction. The hot water, high mineral content, and the RNA that may have been delivered by comets would have a nice witch's brew for life to start in.

I'll have to ask Pensioner if he remembers it one way or the other.

There's no known law of physics that prohibits the production of a self-replicating molecule, the one thing we do know about such a thing is that the molecular make up will be, by definition, complex and require the interaction of many elements. How many generations of stellar evolution are required to produce these elements is still something to be discovered.

[mistermack]

I favor the other direction. The hot water, high mineral content, and the RNA that may have been delivered by comets would have a nice witch's brew for life to start in.

I'll have to ask Pensioner if he remembers it one way or the other.

If heat was a plus though, you wouldn't need the hot smokers, because the oceans started off at boiling point ( or probably well above 100 degrees ) and gradually cooled. So the Earth was one huge hot smoker to begin with.

[Gawdzilla Sama]

I favor the other direction. The hot water, high mineral content, and the RNA that may have been delivered by comets would have a nice witch's brew for life to start in.

I'll have to ask Pensioner if he remembers it one way or the other.

If heat was a plus though, you wouldn't need the hot smokers, because the oceans started off at boiling point ( or probably well above 100 degrees ) and gradually cooled. So the Earth was one huge hot smoker to begin with.

And the time for life to begin would be shorter because the seas would have to cool down less.

[mistermack]

It must have been very weird when the Earth was cooling.
The oceans must have had a level at which they boiled, because the pressure increases as you go deeper.
So as the Earth cooled, the boiling depth must have gradually got shallower and shallower.
And the atmospheric pressure must have been enormous, if there was a huge weight of water vapour being boiled off and condensing.
And the greenhouse effect would have been dramatic, as water vapour is the main greenhouse gas.
The storms must have been fantastic. Plenty of lightning to start things off.

[Azathoth]

4 days

[Tero]

A lot of the water arrived on earth after the crust had cooled. But before the biblical flood.

[Tero]

Mars is made of the similar elements as earth, silicon, iron, more sulfur.
http://en.wikipedia.org/wiki/Geology_of_Mars

I would imagine many planets to be made of the same stuff in other solar systems. So you would not have any solid planets until second generation stars.

Our Sun is a seond or third generation star. Second generation stars do not just burn hydrogen, they also burn heavier elements, like helium and metals (elements heavier than hydrogen and helium), and were formed from supernova explosions (the debris of exploded population II stars).

[mistermack]

Mars is made of the similar elements as earth, silicon, iron, more sulfur.
http://en.wikipedia.org/wiki/Geology_of_Mars

I would imagine many planets to be made of the same stuff in other solar systems. So you would not have any solid planets until second generation stars.

Our Sun is a seond or third generation star. Second generation stars do not just burn hydrogen, they also burn heavier elements, like helium and metals (elements heavier than hydrogen and helium), and were formed from supernova explosions (the debris of exploded population II stars).

Yes. But not all stars take billions of years to burn out.
The bigger ones that end in a supernova have a much shorter life than our sun. And the bigger they are, the sooner they go supernova. The biggest ones can last as little as a million years.
So you may possibly have had second and third generation stars quite quickly after the big bang, if you had a sequence of super massive stars one after another.

[Gawdzilla Sama]

So, we haven't nailed it down to one billion-year window yet?

[mistermack]

So, we haven't nailed it down to one billion-year window yet?

Well, as the oldest stars yet observed are 13.2 billion years old.
So if some were maximum size at that time, and went supernova at one million years old, followed by another one million years later, and another soon after, you have 3rd generation stars 13,195 million years ago. Take another 500 million years for an Earth-like planet to cool, and life could start then.
That's my estimate. 12,695 years ago.

[Clinton Huxley]

So, we haven't nailed it down to one billion-year window yet?

Well, as the oldest stars yet observed are 13.2 billion years old.
So if some were maximum size at that time, and went supernova at one million years old, followed by another one million years later, and another soon after, you have 3rd generation stars 13,195 million years ago. Take another 500 million years for an Earth-like planet to cool, and life could start then.
That's my estimate. 12,695 years ago.

So where are they? Just thinking of the Fermi paradox. If life has been around for 12 billion years, we might expect to find a few beer bottles that the aliens threw out of the UFO window.