Origin of the Elements

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JohnD
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Origin of the Elements

Post by JohnD » Tue Mar 29, 2016 9:58 am

There's a new programme presented by Prof Jim Al-Khalili on BBC-TV, The Beginning and End of the Universe: http://www.bbc.co.uk/programmes/b07591m ... des/player
Only the first part, Beginning, has been broadcast to date, the second, The End, is tonight.

In the first part, Prof Jim said that the elements heavier than Hydrogen or Helium were formed in the first seconds after the Big Bang, in fact fifteen seconds after (!), when expansion cooled the primordial soup of protons and electrons down enough, and while most formed Hydrogen, a small proportion got together to form the bigger atoms. When I understood that this transmutation occurred in supernovae, long, long after that, as the first and second generations of stars came to the end of their lives.

Is this an alternative theory, a parallel way for heavier atoms to arise, or did I misunderstand what he said?

JOhn

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neufer
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Re: Origin of the Elements

Post by neufer » Tue Mar 29, 2016 1:16 pm

JohnD wrote:
There's a new programme presented by Prof Jim Al-Khalili on BBC-TV, The Beginning and End of the Universe: http://www.bbc.co.uk/programmes/b07591m ... des/player
Only the first part, Beginning, has been broadcast to date, the second, The End, is tonight.

In the first part, Prof Jim said that the elements heavier than Hydrogen or Helium were formed in the first seconds after the Big Bang, in fact fifteen seconds after (!), when expansion cooled the primordial soup of protons and electrons down enough, and while most formed Hydrogen, a small proportion got together to form the bigger atoms. When I understood that this transmutation occurred in supernovae, long, long after that, as the first and second generations of stars came to the end of their lives.

Is this an alternative theory, a parallel way for heavier atoms to arise, or did I misunderstand what he said?
Channel 4 video is not available to those of us in the colonies but it should state that ONLY the elements Hydrogen & Helium were formed in the first seconds after the Big Bang. This issue was decided long ago as a compromise between George Gamow (=> everything created in the Big Bang) and Fred Hoyle (=> everything created in stars). [Check out the recent book ‘Brilliant Blunders,’ by Mario Livio]
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JohnD
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Re: Origin of the Elements

Post by JohnD » Tue Mar 29, 2016 2:25 pm

Thank you for reinforcing my belief, neufer!

I've watched the prog again, in which Al-Khalili is discussing the history of cosmology, and the "Alphabetical Article", by Alpher, Bethe and Gamow which proposed Big Bang nucleosynthesis (as I now learn to call it). He never got to Eddington's stellar nucleosynthesis, which is what I thought was accepted theory, not in that episode, anyway. I wonder if that bit fell out onto the cutting room floor, in his or the producer's excitement at telling of some of the lesser known thinkers in cosmology, Lemaitre (expanding universe) and Payne (Preponderance of Hydrogen and Helium), who were eventually proved correct.

I'll watch Episode 2 and hope he tells the full story.
John

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Re: Origin of the Elements

Post by Fred the Cat » Tue Mar 29, 2016 2:50 pm

JohnD wrote:Thank you for reinforcing my belief, neufer!

I've watched the prog again, in which Al-Khalili is discussing the history of cosmology, and the "Alphabetical Article", by Alpher, Bethe and Gamow which proposed Big Bang nucleosynthesis (as I now learn to call it). He never got to Eddington's stellar nucleosynthesis, which is what I thought was accepted theory, not in that episode, anyway. I wonder if that bit fell out onto the cutting room floor, in his or the producer's excitement at telling of some of the lesser known thinkers in cosmology, Lemaitre (expanding universe) and Payne (Preponderance of Hydrogen and Helium), who were eventually proved correct. :)

I'll watch Episode 2 and hope he tells the full story.
John
I like your reference to the "alphabetical article". It's nice to see physicists have senses of humor and are willing to share their hard work for the sake of a good story.
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JohnD
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Re: Origin of the Elements

Post by JohnD » Tue Mar 29, 2016 3:31 pm

Not mine!
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neufer
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Re: Origin of the Elements

Post by neufer » Tue Mar 29, 2016 5:01 pm

Fred the Cat wrote:
I like your reference to the "alphabetical article". It's nice to see physicists have senses of humor and are willing to share their hard work for the sake of a good story.
  • Well... at least George Gamow had a sense of humor.
https://en.wikipedia.org/wiki/Alpher%E2%80%93Bethe%E2%80%93Gamow_paper wrote:
<<In his 1952 book, The Creation of the Universe, Gamow explained Hans Bethe's association with the theory thus:
  • The results of these calculations were first announced in a letter to The Physical Review, April 1, 1948. This was signed Alpher, Bethe, and Gamow, and is often referred to as the 'alphabetical article.' It seemed unfair to the Greek alphabet to have the article signed by Alpher and Gamow only, and so the name of Dr. Hans A. Bethe (in absentia) was inserted in preparing the manuscript for print. Dr. Bethe, who received a copy of the manuscript, did not object, and, as a matter of fact, was quite helpful in subsequent discussions. There was, however, a rumor that later, when the alpha, beta, gamma theory went temporarily on the rocks, Dr. Bethe seriously considered changing his name to Zacharias."
The close fit of the calculated curve and the observed abundances represents the results of later calculations carried out on the electronic computer of the National Bureau of Standards by Ralph Alpher and R. C. Herman (who stubbornly refuses to change his name to Delter.) Alpher, at the time only a graduate student, was generally dismayed by the inclusion of Bethe's name on this paper. He felt that the inclusion of another eminent physicist would overshadow his personal contribution to this work and prevent him from receiving proper recognition for such an important discovery. He expressed resentment over Gamow's whimsy as late as 1999.>>
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Re: Origin of the Elements

Post by JohnD » Fri Apr 01, 2016 2:11 pm

The second episode of Prof Al-Khalili's 'Rise and Fall of the Universe' programme did indeed spend some time with Fred Hoyle and his discovery of stellar nucleogenesis. For those you of not dwelling in Outer Darkness, it's on the iPlayer at http://www.bbc.co.uk/iplayer/episode/b0 ... -2-the-end.

Obviously, you cannot make a two-episode programme on such a subject, and make it a coherent course in The History of Cosmology. But he might have mentioned that Hoyle's work did supercede Bethe and Gamow's. When he made so much of Einstein's Big Mistake, a sort of compensation for Hoyle being wrong about the Big Bang.

John