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Why is hydrogen the most common element in the universe?

  1. Aug 10, 2010 #1
    i understand that everything else is less as they are (in turn) made from hydrogen, but why was so much of hydrogen made in the big bang?

    i got a feeling because one proton and one electron is stable. (similarly, helium was produced as 2 nucleons + 2 electrons is also very stable) but i've never been 100% sure
  2. jcsd
  3. Aug 10, 2010 #2


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    Helium is actually more stable than hydrogen. This is why stars and hydrogen bombs can create huge amounts of energy by fusing hydrogen into helium. In fact, in terms of stability of the nucleus (as measured by nuclear binding energy), iron-56 is the most stable. So, the stability of the atom does not seem like a good explanation for the abundance of hydrogen in the universe.

    Likely (and someone please correct me if I'm wrong because I'm not an astrophysicist), hydrogen is the easiest atom to form (forms at the fastest rate) whereas the other types of atoms are much more difficult to form as they require extreme temperatures and pressures in order for protons to bind and form heavier nuclei. In chemistry terms, we can probably think of the formation of hydrogen in the early universe as a process under kinetic control rather than one under thermodynamic control.
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