Big Bang nucleosynthesis is the process by which the light elements, chiefly hydrogen, helium and small amounts of lithium, were formed from protons and neutrons during the first few minutes after the Big Bang, while the universe was still hot and dense enough to fuse nuclei. The predicted abundances of these primordial elements, especially the roughly 25 percent helium fraction by mass, closely match what is observed in the oldest, least processed matter in the universe, making the theory one of the strongest pieces of evidence for the Big Bang model. Nearly all heavier elements were produced later, inside stars and in stellar explosions, rather than during this early period.
Reader Challenges (0 open reader challenges)
No disputes yet. Spotted an error or a better source? Open the first one.
Sign in to dispute this or suggest a correction.
View At A Past Year
The atlas records no dated fact of its own for this entry, so there is no other year to choose.