Editing Nucleosynthesis (section)

===Cosmic ray spallation===
{{main|Cosmic ray spallation}}
Cosmic ray spallation process reduces the atomic weight of interstellar matter by the impact with cosmic rays, to produce some of the lightest elements present in the universe (though not a significant amount of [[deuterium]]). Most notably spallation is believed to be responsible for the generation of almost all of <sup>3</sup>He and the elements [[lithium]], [[beryllium]], and boron, although some {{SimpleNuclide|Lithium|7}} and {{SimpleNuclide|Beryllium|7}} are thought to have been produced in the Big Bang. The spallation process results from the impact of [[cosmic rays]] (mostly fast protons) against the [[interstellar medium]]. These impacts fragment carbon, nitrogen, and oxygen nuclei present. The process results in the light elements beryllium, boron, and lithium in the cosmos at much greater abundances than they are found within solar atmospheres. The quantities of the light elements <sup>1</sup>H and <sup>4</sup>He produced by spallation are negligible relative to their primordial abundance.

Beryllium and boron are not significantly produced by stellar fusion processes, since [[beryllium-8|<sup>8</sup>Be]] has an extremely short half-life of {{val|8.2|e=-17}} seconds.<ref>{{cite journal |title=A New Approach for Calculating the Alpha-Decay Half-Life for the Heavy and Super-heavy Elements and an Exact A Priori Result for Beyllium-8 |url=https://www.osti.gov/servlets/purl/1773479 |website=osti.gov |date=2021 |publisher=U.S. Department of Energy Office of Scientific and Technical Information |doi=10.2172/1773479 |access-date=17 April 2024 |last1=Surdoval |first1=Wayne |last2=Berry |first2=David |osti=1773479 }}</ref>