The Two Big BangsWhen scientists say “the Big Bang” they mean...
The Two Big Bangs
When scientists say “the Big Bang” they mean two possible things. But only one of them is still correct.
When cosmologists — that’s the sub-field of astrophysics dealing with the origin and evolution of the Universe — speak about the Big Bang, they mean one of two things:
- The hot, dense, expanding state that our observable Universe emerged from, that expanded, slowed, cooled, and gave rise to elements, atoms, stars, molecules, planets, and eventually us.
- The initial singularity that represents the birth of space and time.
The only problem is, while these two explanations were interchangeable back in say, the 1960s, they no longer are.
Image credit: Cosmic Inflation by Don Dixon
Via Medium (Starts With a Bang)