Tuesday, August 08, 2017

Gamow's Genesis

From Wikipedia,

George Gamow (March 4 [O.S. February 20] 1904 – August 19, 1968), born Georgiy Antonovich Gamov (RussianГео́ргий Анто́нович Га́мовIPA: [ɡʲɪˈorɡʲɪj ɐnˈtonəvʲɪtɕ ˈɡaməf]), was a theoretical physicist and cosmologist. He was an early advocate and developer of Lemaître's Big Bang theory. He discovered a theoretical explanation of alpha decay via quantum tunneling, and worked on radioactive decay of the atomic nucleusstar formationstellar nucleosynthesis and Big Bang nucleosynthesis (which he collectively called nucleocosmogenesis), and molecular genetics.

Gamow penned his tongue in cheek version of Genesis to highlight the "mistake" that the Big Bang doesn't produce any heavy elements such as Carbon and Oxygen. The Big Bang made protons and neutrons (Mass = 1) from quarks, Deuterium from a proton and neutron (Mass = 2), Tritium from two protons and a neutron (Mass = 3) and Helium (aka alpha particle) from two protons and two neutrons (Mass = 4). Here the primordial fusing stopped. There is no stable Mass = 5 nucleus. From Gamow:

In the beginning God created Radiation and Ylem. And the Ylem was without shape or number, and the nucleons were rushing madly upon the face of the deep. 
And God said: “Let there be mass two.” And there was mass two. And God saw deuterium, and it was good.  
And God said: “Let there be mass three.” And there was mass three. And God saw tritium, and it was good.  
And God continued to call numbers until He came to the transuranium elements. But when He looked back on his work, He saw that it was not good. In the excitement of counting, He had missed calling for mass five, and so, naturally, no heavier elements could have been formed.  
God was very disappointed by that slip and wanted to contract the universe again and start everything from the beginning. But that would be much too simple. Instead, being Almighty, God decided to make heavy elements in the most impossible way.  
And so God said: “Let there be Hoyle.” And there was Hoyle. And God saw Hoyle and told him to make heavy elements in any way he pleased.  
And so Hoyle decided to make heavy elements in stars, and to spread them around by means of supernova explosions. But in doing so, Hoyle had to follow the blueprint of abundances which God prepared earlier when He had planned to make the elements from Ylem. 
Thus, with the help of God, Hoyle made all heavy elements in stars, but it was so complicated that neither Hoyle, nor God, nor anybody else can now figure out exactly how it was done.

The reference to Hoyle was a tribute to his nucleosynthesis work, i.e. the explanation that the heavier elements needed for life are formed in the bellies of stars, then blasted into space via supernovae explosions.

But did Hoyle really rescue God from a design flaw? He did not. A stable Mass = 5 nucleus would have allowed primordial fusion to proceed, depleting protons (a proton by another name is Hydrogen) and would have robbed the stars (if they had formed) of their fuel. Stars need abundant Hydrogen to fuse and release their life-sustaining heat. The heavier elements can be made inside stars because of the enormous temperatures and pressures. However, the lack of a Mass = 5 stable nucleus--which stopped the primordial fusion in the early, pre-star, Big Bang environment, still slows down the process even inside stars--so that they (If they are mid-sized, like our star) burn their field slowly, over billions of years. 

The missing Mass = 5 stable nucleus is not a bug, it's a feature.

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