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In physical cosmology, the Alpher-Bethe-Gamow paper (or αβγ paper) was created by Ralph Alpher, at the time a physics PhD student, and his advisor George Gamow. Their work, which would become the subject of Alpher's PhD thesis, argued that the big bang would be expected to create hydrogen, helium and heavier elements in the correct proportions to explain their abundance in the early universe. While the original theory neglected a number of processes important to the formation of heavy elements, subsequent developments showed that big bang nucleosynthesis is consistent with the observed constraints on all primordial elements.
Bethes name
Main shortcoming of the theory The theory originally proposed that all atomic nuclei are produced by the successive capture of neutrons, one mass unit at a time. However, later study challenged the universality of the successive capture theory. No element was found to have a stable isotope with an atomic mass of five or eight. Physicists soon noticed that these mass gaps would hinder the production of elements beyond helium. Just as it's impossible to climb a staircase one step at a time when one of the steps is missing, this discovery meant that the successive capture theory could not account for higher elements. It was eventually recognized that most of the heavy elements observed in the present universe are the result of stellar nucleosynthesis in stars, a theory largely developed by Bethe. However, the Alpher-Bethe-Gamow theory does correctly explain the relative abundances of the isotopes of hydrogen and helium. Taken together, these account for more than 99% of the baryonic mass of the universe. Today, nucleosynthesis is widely considered to have taken place in two stages: formation of hydrogen and helium according to the Alpher-Bethe-Gamow theory, and stellar nucleosynthesis of higher elements according to Bethe's later theories. | ||||||||||
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