Evidence for Star Formation: 250 Million Years post Big Bang:

[beecee]

https://phys.org/news/2018-05-alma-most-distant-oxygen-universe.html

Astronomers find evidence for stars forming just 250 million years after Big Bang

May 16, 2018, National Radio Astronomy Observatory

Not long after the Big Bang, the first generations of stars began altering the chemical make-up of primitive galaxies, slowly enriching the interstellar medium with basic elements such as oxygen, carbon, and nitrogen. Finding the earliest traces of these common elements would shed important light on the chemical evolution of galaxies, including our own.
 

New observations with the Atacama Large Millimeter/submillimeter Array (ALMA) reveal the faint, telltale signature of oxygen coming from a galaxy at a record-setting distance of 13.28 billion light-years from Earth, meaning we are observing this object it as it appeared when the universe was only 500 million years old, or less than 4 percent its current age.

For such a young galaxy, known as MACS1149-JD1, to contain detectable traces of oxygen, it must have begun forging stars even earlier: a scant 250 million years after the Big Bang. This is exceptionally early in the history of the universe and suggests that rich chemical environments evolved quickly.

Read more at: https://phys.org/news/2018-05-alma-most-distant-oxygen-universe.html#jCp

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the paper:

https://www.nature.com/articles/s41586-018-0117-z

The onset of star formation 250 million years after the Big Bang:

Abstract:

A fundamental quest of modern astronomy is to locate the earliest galaxies and study how they influenced the intergalactic medium a few hundred million years after the Big Bang1,2,3. The abundance of star-forming galaxies is known to decline4,5 from redshifts of about 6 to 10, but a key question is the extent of star formation at even earlier times, corresponding to the period when the first galaxies might have emerged. Here we report spectroscopic observations of MACS1149-JD16, a gravitationally lensed galaxy observed when the Universe was less than four per cent of its present age. We detect an emission line of doubly ionized oxygen at a redshift of 9.1096 ± 0.0006, with an uncertainty of one standard deviation. This precisely determined redshift indicates that the red rest-frame optical colour arises from a dominant stellar component that formed about 250 million years after the Big Bang, corresponding to a redshift of about 15. Our results indicate that it may be possible to detect such early episodes of star formation in similar galaxies with future telescopes.

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Hmm, interesting in as much as would or could it be suggested that extrapolating the evidence for early star and element formation, one could reasonably suggest that life via abiogenesis may have also arisen early? Obviously not life on Earth but an early form of universal life and abiogenesis. Perhaps the foundation of another discussion/debate in another more appropriate forum?

Edited May 16, 2018 by beecee

[T. McGrath]

Whenever discussing stars we also need to take into consideration all the other "stuff" that formed in addition to the star.  I have no doubt that the first Population III stars would have had planets, asteroids, comets, and everything else we find in solar systems.  However, it has been suggested that these first stars would have been massive, anywhere from 100 to 1,000 solar masses.  If that is true then these first stars would have had very short lives indeed.  Perhaps just a few million years.  While that may be sufficient time to produce the first 26 elements on the Periodic Table, it is far too short a time for life to develop.  At best life would just be getting started, only to be wiped out by the resulting hypernova when the Pop III star dies.

I think life has its best shot beginning with Pop II stars.  The metal-poor stars in the halo of our Milky Way, for example, have been dated to 12+ billion years.  Since we only have one example to go by, it is rather difficult to say with any certainty how long it takes to evolve beyond primordial life.  I would imagine that it very much depends on the conditions.  On Earth it took just over 700 million years before life first appeared, and then another 3.3+ billion years before we get to the Cambrian.  That is a long time for a planet to remain relatively stable.  Too long for any star with greater than just a couple of solar masses.

Given that Pop. III stars would have been short lived, the Pop. II stars would have formed shortly after the Pop. III stars.  Certainly within the first billion years after the Big Bang.  Therefore, I would not rule out the possibility of life being 12.8+ billion years old.

Source:
The Formation of First Stars. I. The Primordial Star-forming Cloud - The Astrophysical Journal, Volume 564, Number 1, 2002 (free preprint)

Edited May 21, 2018 by T. McGrath

[Strange]

9 hours ago, T. McGrath said:

Whenever discussing stars we also need to take into consideration all the other "stuff" that formed in addition to the star.  I have no doubt that the first Population III stars would have had planets, asteroids, comets, and everything else we find in solar systems. 

Remember that when the first stars formed there would have been no heavier elements to form planets asteroids, etc. The absence of those elements is the reason why the first stars are so large and short-lived (for reasons I don't really understand...)

[StringJunky]

1 hour ago, Strange said:

Remember that when the first stars formed there would have been no heavier elements to form planets asteroids, etc. The absence of those elements is the reason why the first stars are so large and short-lived (for reasons I don't really understand...)

Higher density and population of gas clouds by virtue of the universe being smaller?

Edited May 21, 2018 by StringJunky

[Mordred]

12 hours ago, Strange said:

Remember that when the first stars formed there would have been no heavier elements to form planets asteroids, etc. The absence of those elements is the reason why the first stars are so large and short-lived (for reasons I don't really understand...)

 

 The more massive stars were incredibly hot compared to the stars today plus the blackbody temperature of the universe itself was far hotter as well.

[StringJunky]

11 minutes ago, Mordred said:

 

 The more massive stars were incredibly hot compared to the stars today plus the blackbody temperature of the universe itself was far hotter as well.

By virtue of being smaller?

[Mordred]

Yes but more accurately the higher density past. 

[StringJunky]

11 minutes ago, Mordred said:

Yes but more accurately the higher density past. 

Right.

[Mordred]

A quick back of envelope calculation

250 million years scale factor 0.000724 gives a temperature by the inverse scale factor relation of 1,381.22 kelvin

[StringJunky]

2 minutes ago, Mordred said:

A quick back of envelope calculation

250 million years scale factor 0.000724 gives a temperature by the inverse scale factor relation of 1,381.22 kelvin

What's the temperature now?

[Mordred]

2.73 kelvin today

[StringJunky]

10 minutes ago, Mordred said:

2.73 kelvin today

From red hot/melting iron temperature to  that is a pretty big difference.  Does the temperature drop in direct proportion to the acceleration of the expansion?

[Mordred]

Roughly inverse to the scale factor

[latex] T\propto\frac{1}{a}[/latex]

 keep in mind its an approximation its more accurate to use Bose and Fermi Dirac statistics but far more complex as one has to account for each particle species. However its considered readonably accurate

scale factor is a dimensionless value comparing radius then to radius now

[latex]a=\frac{r}{\dot{r}}[/latex]

Edited May 22, 2018 by Mordred

[StringJunky]

15 minutes ago, Mordred said:

Roughly inverse to the scale factor

T∝1a

 keep in mind its an approximation its more accurate to use Bose and Fermi Dirac statistics but far more complex as one has to account for each particle species. However its considered readonably accurate

scale factor is a dimensionless value comparing radius then to radius now

Missing close brace

Rough and ready will do me.    Thanks. 

[Mordred]

Your welcome lol I cheated a bit and used the cosmocalc in my signature to get the scale factor for then. It uses the appropriate formulas taking the evolution of matter, radiation and lambda into account but has limits to how far back it will go. 

Earliest scale factor it allows is 0.00005 

Edited May 22, 2018 by Mordred

[beecee]

3 hours ago, Mordred said:

2.73 kelvin today

Is there a relationship between the temperature of the CMBR and the theoretical application of Hawking radiation?

[Strange]

7 minutes ago, beecee said:

Is there a relationship between the temperature of the CMBR and the theoretical application of Hawking radiation?

Only in that an (isolated) black hole would have to be much smaller then to be able to lose mass by Hawking radiation faster than it gained mass from the CMB.

[beecee]

13 minutes ago, Strange said:

Only in that an (isolated) black hole would have to be much smaller then to be able to lose mass by Hawking radiation faster than it gained mass from the CMB.

But as the CMBR continues to drop, a stage will be reached where the CMBR is lower then Hawking radiation and then any size BH, many many  of trillions of years hence, will evaporate. The universe of course will be long dead by this stage, BH's being the last to go...

[Mordred]

Correct in order for a BH to lose mass by Hawking radiation the Blackbody temp of the event horizon must be greater than that of the CMB. If the CMB is hotter then the BH will absorb the heat and gain mass.

[beecee]

9 hours ago, Mordred said:

Correct in order for a BH to lose mass by Hawking radiation the Blackbody temp of the event horizon must be greater than that of the CMB. If the CMB is hotter then the BH will absorb the heat and gain mass.

Which in reality and logically, adds some reasonable validity to Hawking Radiation, despite the fact that actually detecting it [HR} is near impossible as it is drowned out by the background. Correct?

[Mordred]

Ir would take a BH smaller than the mass of the moon to radiate. We haven't found any that match that criteria lol. At least not in the universe with todays age. The possibility exists for small BHs in the distant past ie primordial BH's when the CMB itself was much hotter but good luck detecting radiation at those extreme ranges.