The idea of the big bang comes from Hubble Time, where we extrapolate the age of the universe using Hubble’s constant(the rate of expansion of the universe). We assume Hubble’s constant to be constant(spoilers it isn’t) and work backwards to see how long ago the universe would be contained within a singularity. That’s the basic idea of the big bang, however the physics behind it all gets very hazy as we get closer and closer to it. I’m talking 10^-20 seconds after the big bang close
LukeDankwalker t1_j79v44c wrote
Reply to Serious question by Unable_Region7300
The idea of the big bang comes from Hubble Time, where we extrapolate the age of the universe using Hubble’s constant(the rate of expansion of the universe). We assume Hubble’s constant to be constant(spoilers it isn’t) and work backwards to see how long ago the universe would be contained within a singularity. That’s the basic idea of the big bang, however the physics behind it all gets very hazy as we get closer and closer to it. I’m talking 10^-20 seconds after the big bang close