The Big Bang teaches us that our expanding, cooling universe used to be younger, denser, and hotter in the past.
However, extrapolating all the way back to a singularity leads to predictions that disagree with what we observe.
Instead, cosmic inflation preceded and set up the Big Bang, changing our cosmic origin story forever.
October 13, 2021
Surprise: the Big Bang isn’t the beginning of the universe anymore
[Data exists back to about one second from the beginning.of the universe! Prior to that it’s speculation. The Big Bang from a singularity hypothesis doesn’t match some of the early data. Cosmic inflation is a better match.