edit In cosmology, Big Bang nucleosynthesis (or primordial nucleosynthesis) refers to the production of nuclei other than H-1, the normal, light hydrogen, during the early phases of the universe, shortly after the Big Bang. It is believed to be responsible for the formation of hydrogen (H-1 or H), its isotope deuterium (H-2 or D), the helium isotopes He-3 and He-4, and the lithium isotope Li-7. Big Bang nucleosynthesis - Sequence of BBN. Big Bang nucleosynthesis begins about one ...

Including:

• Big Bang nucleosynthesis - Sequence of BBN
• Big Bang nucleosynthesis - History of Big Bang nucleosynthesis
• Big Bang nucleosynthesis - Heavy elements
• Big Bang nucleosynthesis - Helium-4
• Big Bang nucleosynthesis - Deuterium
• Big Bang nucleosynthesis - Status and Implications of BBN
• Big Bang nucleosynthesis - Non-standard BBN

Read more here: » Big Bang nucleosynthesis: Encyclopedia - Big Bang nucleosynthesis

The theory of BBN gives a detailed mathematical description of the production of the light "elements" deuterium, helium-3, helium-4, and lithium-7. Specifically, the theory yields precise quantitative predictions for the mixture of these elements, that is, the primordial abundances. As noted above, in the standard picture of BBN, all of the light element abundances depend on the amount of ordinary matter (baryons) relative to radiation (photons). Since the universe is homogeneous, it has one unique (but initially unknown to us) value ...

See also:

Big Bang nucleosynthesis, Big Bang nucleosynthesis - Sequence of BBN, Big Bang nucleosynthesis - History of Big Bang nucleosynthesis, Big Bang nucleosynthesis - Heavy elements, Big Bang nucleosynthesis - Helium-4, Big Bang nucleosynthesis - Deuterium, Big Bang nucleosynthesis - Status and Implications of BBN, Big Bang nucleosynthesis - Non-standard BBN

Read more here: » Big Bang nucleosynthesis: Encyclopedia II - Big Bang nucleosynthesis - Status and Implications of BBN

Big Bang nucleosynthesis begins about one minute after the Big Bang, when the universe has cooled enough to form stable protons and neutrons, after baryogenesis. From simple thermodynamical arguments, one can calculate the fraction of protons and neutrons based on the temperature at this point. This fraction is in favour of protons, because the higher mass of the neutron results in a spontaneous decay of neutrons to protons with a half-life of about 15 minutes. One feature of BBN is that the physical laws and constants that govern the behavi ...

See also:

Big Bang nucleosynthesis, Big Bang nucleosynthesis - Sequence of BBN, Big Bang nucleosynthesis - History of Big Bang nucleosynthesis, Big Bang nucleosynthesis - Heavy elements, Big Bang nucleosynthesis - Helium-4, Big Bang nucleosynthesis - Deuterium, Big Bang nucleosynthesis - Status and Implications of BBN, Big Bang nucleosynthesis - Non-standard BBN

Read more here: » Big Bang nucleosynthesis: Encyclopedia II - Big Bang nucleosynthesis - Sequence of BBN

In addition to the standard BBN scenario there are numerous non-standard BBN scenarios. These should not be confused with non-standard cosmology: a non-standard BBN scenario assumes that the Big Bang occurred, but insert additional physics in order to see how this affects elemental abundances. These pieces of additional physics include relaxing or removing the assumption of homogeneity, or inserting new particles such as massive neutrinos. There have been, and continue to be, various reasons for researching non-standard BBN. The first ...

See also:

Big Bang nucleosynthesis, Big Bang nucleosynthesis - Sequence of BBN, Big Bang nucleosynthesis - History of Big Bang nucleosynthesis, Big Bang nucleosynthesis - Heavy elements, Big Bang nucleosynthesis - Helium-4, Big Bang nucleosynthesis - Deuterium, Big Bang nucleosynthesis - Status and Implications of BBN, Big Bang nucleosynthesis - Non-standard BBN

Read more here: » Big Bang nucleosynthesis: Encyclopedia II - Big Bang nucleosynthesis - Non-standard BBN