The quark soup had cooled to an ionised plasma of photons, electrons, positrons, neutrinos, protons and neutrons. These conditions have a massive flux of free neutrons and the various nuclei are able absorb one or more of these neutrons, undergo beta decay, absorb another neutron or neutrons, another beta decay After aboutyears the process of recombination occurred.
The capture of a neutron increases the mass of a nucleus; subsequent radioactive beta decay converts a neutron into a proton with ejection of an electron and an antineutrinoleaving the mass practically unchanged. Due to the thermochemistry of the various nuclear processes, each shell of nucleosynthesis proceeds on an accelerating time scale and Si burns to Fe in hours.
In the years immediately before World War II, Hans Bethe first elucidated those nuclear mechanisms by which hydrogen is fused into helium. The period of baryionic matter formation: One of the most famous scientific discoveries of this century is the equivalence of matter and energy.
The important point is that the prediction depends critically on the density of baryons ie neutrons and protons at the time of nucleosynthesis. Subsequently, Hoyle's picture was expanded during the s by contributions from William A.
Big Bang nucleosynthesis Big Bang nucleosynthesis  occurred within the first three minutes of the beginning of the universe and is responsible for much of the abundance of 1H protium2H D, deuterium3He helium-3and 4He helium Some of those others include the r-processwhich involves rapid neutron captures, the rp-processand the p-process sometimes known as the gamma processwhich results in the photodisintegration of existing nuclei.
The deuterium abundance only increases to a point because it is an intermediate to the formation of helium. When the chemicals hydrogen and helium mix up, it then becomes the particle or isotope known as Be, which has the unstable atomic mass of 8.
Star formation has occurred continuously in galaxies since that time.
BurbidgeFowler and Hoyle  is a well-known summary of the state of the field in Arthur Stanley Eddington first suggested inthat stars obtain their energy by fusing hydrogen into helium and raised the possibility that the heavier elements may also form in stars.
The other two consequences of these collisions involve interactions between particles as they collided.The subsequent nucleosynthesis of the elements (including all carbon, all oxygen, etc.) occurs primarily in stars either by nuclear fusion or nuclear fission.
Precisely which elements are involved in nucleosynthesis depends on the age and mass of the star. The most prevalent reaction in smaller stars like our Sun is the fusion of hydrogen into helium by the proton-proton chain ; in more massive stars this fusion occurs via the carbon cycle.
This concept also applies in nucleosynthesis of heavier elements. Once the bottleneck is overcome, the remaining reactions are able to be completed.
In the early universe, once the deuterium bottleneck was cleared, the newly formed deuterium could undergo further nuclear reactions to form Helium.
Stellar nucleosynthesis is the theory explaining the creation (nucleosynthesis) of chemical elements by nuclear fusion reactions between atoms within stars. Stellar nucleosynthesis has occurred continuously since the original creation of hydrogen, helium and lithium during the Big Bang.
Big Bang Nucleosynthesis The Universe's light-element abundance is another important criterion by which the Big Bang hypothesis is verified. It is now known that the elements observed in the Universe were created in either of two ways.
Apr 16, · The term nucleosynthesis refers to the formation of heavier elements, atomic nuclei with many protons and neutrons, from the fusion of lighter elements. The Big Bang theory predicts that the early universe was a very hot place.Download