The Big Crunch - Theory Number Four

The big crunch is an idea that's really been around quite a long time. It was the idea that was sort of most accepted as likely in sort of the 1960s. The idea behind the big crunch is that we observe that the universe is expanding. But if it started to contract, then what we would see is all these distant galaxies kind of rushing toward us. And worse than that, all of the radiation in the universe would also be compressed.