The Universe

Evidence of the Big Bang

What evidence is there for the Big Bang based on the nature of matter in the universe?

The distribution of elements by mass in the early universe—75 percent hydrogen, 25 percent helium, and a tiny trace of other, heavier elements—matches the predictions of a hot Big Bang. This kind of elemental distribution probably came about because, as the universe cooled and expanded, there was only a very short amount of time (about three minutes!) when conditions in the universe could support the creation of atomic nuclei from subatomic particles.


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