The first nuclei, including most of the helium and all of the deuterium in the universe, were theoretically created during big bang nucleosynthesis, about 3
minutes after the big bang.
In principle, if we run the clock backwards far enough, we could observe the very first stars, aka «Population III stars»: those formed from only those elements created in the first few
minutes after the big bang.
Not exact matches
CE: The
big bang produced deuterium 3 — 20
minutes after the universe began, 13.8 billion years ago.