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  2. Eddington number - Wikipedia

    en.wikipedia.org/wiki/Eddington_number

    In astrophysics, the Eddington number, N Edd, is the number of protons in the observable universe. Eddington originally calculated it as about 1.57 × 10 79 ; current estimates make it approximately 10 80 .

  3. Big Bang nucleosynthesis - Wikipedia

    en.wikipedia.org/wiki/Big_Bang_nucleosynthesis

    The problem was that while the concentration of deuterium in the universe is consistent with the Big Bang model as a whole, it is too high to be consistent with a model that presumes that most of the universe is composed of protons and neutrons. If one assumes that all of the universe consists of protons and neutrons, the density of the ...

  4. Observable universe - Wikipedia

    en.wikipedia.org/wiki/Observable_universe

    According to the theory of cosmic inflation initially introduced by Alan Guth and D. Kazanas, [23] if it is assumed that inflation began about 10 −37 seconds after the Big Bang and that the pre-inflation size of the universe was approximately equal to the speed of light times its age, that would suggest that at present the entire universe's ...

  5. Recombination (cosmology) - Wikipedia

    en.wikipedia.org/wiki/Recombination_(cosmology)

    As the universe expanded, it also cooled. Eventually, the universe cooled to the point that the radiation field could not immediately ionize neutral hydrogen, and atoms became energetically favored. [3] The fraction of free electrons and protons as compared to neutral hydrogen decreased to a few parts in 10 000.

  6. Elementary particle - Wikipedia

    en.wikipedia.org/wiki/Elementary_particle

    The number of protons in the observable universe is called the Eddington number. In terms of number of particles, some estimates imply that nearly all the matter, excluding dark matter, occurs in neutrinos, which constitute the majority of the roughly 10 86 elementary particles of matter that exist in the visible universe. [12]

  7. Nucleosynthesis - Wikipedia

    en.wikipedia.org/wiki/Nucleosynthesis

    Diagram illustration the creation of new elements by the alpha process. Nucleosynthesis is the process that creates new atomic nuclei from pre-existing nucleons (protons and neutrons) and nuclei.

  8. Big Bang - Wikipedia

    en.wikipedia.org/wiki/Big_Bang

    The Big Bang is a physical theory that describes how the universe expanded from an initial state of high density and temperature. [1] The concept of an expanding universe was scientifically originated by physicist Alexander Friedmann in 1922 with the mathematical derivation of the Friedmann equations.

  9. Arthur Eddington - Wikipedia

    en.wikipedia.org/wiki/Arthur_Eddington

    In particular, he predicted a number of hydrogen atoms in the Universe 136 × 2 256 ≈ 1.57 × 10 79, or equivalently the half of the total number of particles protons + electrons. [18] He did not complete this line of research before his death in 1944; his book Fundamental Theory was published posthumously in 1948.