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A.DIM
2014-Feb-04, 03:37 AM
Ordinarily it is thought life in the universe could have arisen no earlier than ~10G years ago, only after a second generation of stars had time to die (which created the needed ingredients).

This brief paper (http://arxiv.org/pdf/1312.0613v2.pdf) suggests life could have formed much earlier: 10-17M years after the BB!

Abstract:
In the redshift range 100.(1 +z).137, the cosmic microwave background (CMB) had a temperature of 273373 K (0-100◦C), allowing early rocky planets (if any existed) to have liquid water chemistry on their surface and be habitable, irrespective of their distance from a star. In the standard ΛCDM cosmology, the first star-forming halos within our Hubble volume started collapsing at these redshifts, allowing the chemistry of life to possibly begin when the Universe was merely 1017 million years old. The possibility of life starting when the average matter density was a million times bigger than it is today argues against the anthropic explanation for the low value of the cosmological constant.

And here is a lay-pop version Did Alien Life Evolve Just After the Big Bang? (http://www.space.com/24496-universe-alien-life-habitability-big-bang.html)

Astrophysicist Joshua Winn of the Massachusetts Institute of Technology says about the paper - "In our field, it has become traditional to adopt a definition of a 'potentially habitable' planet as one that has a solid surface and a surface temperature conducive to liquid water, he said. "Many, many papers have been written about the exact conditions under which we might find such planets what type of interior composition, atmosphere, and stellar radiation field. Avi has taken this point to a logical extreme, by pointing out that if those two conditions are really the only important conditions, then there is another way to achieve them, which is to make use of the cosmic microwave background."

Life seems, in my view, an inevitable outcome in our universe at whatever epoch, but likely arose as soon as the ingredients and conditions were present. It has since had ample time to spread ...

eburacum45
2014-Feb-04, 10:00 AM
This warm, apparently clement period occurred when there were very few planets, most of which will have been gas giants rather than rocky worlds. The warm period only lasted a few million years, not long enough for life to develop much complexity.

And there is the problem that in a warm universe there are no temperature gradients and no heat sinks; if life emerged and started to produce waste heat it would cook itself, as there would be nowhere for the heat to go.

But it is still an intriguing possibility. Perhaps life emerged a little later than the warm period, when the universe was not quite uniformly at habitable temperature but there were temperature gradients to exploit. Most of this early emergent life would be extinguished as the universe became cooler and cooler over time; but some might persist.

Cougar
2014-Feb-04, 01:36 PM
[When the Universe was 1017 million years old,] the cosmic microwave background (CMB) had a temperature of 273373 K (0-100o C), allowing early rocky planets (if any existed) to have liquid water chemistry on their surface....

Yeah, if any existed. It is questionable whether the first stars had formed by 10 million years. And before the first stars, all you've got is hydrogen and helium. Where does Loeb imagine these "rocky planets" are coming from?

Noclevername
2014-Feb-04, 01:47 PM
Yeah, if any existed. It is questionable whether the first stars had formed by 10 million years. And before the first stars, all you've got is hydrogen and helium. Where does Loeb imagine these "rocky planets" are coming from?

And the oxygen for water? The CHON for organics? Etc. No stars means not only no planets, but nothing to make life from.

John Mendenhall
2014-Feb-04, 05:50 PM
Interesting idea. Lots of material for SF stories. I'm calling mine "The Oxygen Wars".

A.DIM
2014-Feb-07, 02:04 AM
Yeah, if any existed. It is questionable whether the first stars had formed by 10 million years. And before the first stars, all you've got is hydrogen and helium. Where does Loeb imagine these "rocky planets" are coming from?

The paper is brief, some 14 paragraphs, heavily laden with the maths.

But my understanding is more as Loeb says, that rare "islands" packed with denser matter may have existed in the early universe, and massive, short-lived stars could have formed in them earlier than expected. Explosions of these stars could have seeded the cosmos with heavy elements, and the very first rocky planets would have been born.
These first planets would have been bathed in the warm CMB radiation, and thus, Loeb argues, it would have been possible for them to have liquid water on their surface for several million years.

Noclevername
2014-Feb-07, 12:57 PM
The paper is brief, some 14 paragraphs, heavily laden with the maths.

But my understanding is more as Loeb says, that rare "islands" packed with denser matter may have existed in the early universe, and massive, short-lived stars could have formed in them earlier than expected. Explosions of these stars could have seeded the cosmos with heavy elements, and the very first rocky planets would have been born.
These first planets would have been bathed in the warm CMB radiation, and thus, Loeb argues, it would have been possible for them to have liquid water on their surface for several million years.

And what evidence for these islands of density have we observed?

NoisyAstronomer
2014-Feb-07, 09:51 PM
And what evidence for these islands of density have we observed?

Well, Avi Loeb is very much a theorist. :-)

Regarding regular old planets like we're used to, I read elsewhere that stars probably need to have at least 10% the metallicity that the Sun has today to be able to produce planets from the circumstellar disk. I doubt that would have happened by z~100 though.