The Big Bang Theory

One of the most amazing things that have happened even in my lifetime is the prediction of cosmology. When I started out 40 odd years ago, we thought we knew that the universe began a big bang, some people doubted even then. We thought the universe was about 10 or 20 billion years old. But now, for really very sound scientific reasons, we can say that the universe did start in a big bang, and it's 13 .8 billion years old. o it's not 14, it's not 13, because a decimal point in there, and that's a stunning achievement to know that. And we also know that the laws of physics that apply to tiny particles inside atoms also explains what happened in the big bang. You can't have one without the other. A very neat example of this is that when you apply nuclear physics, that kind of physics to understand how stars work, you find out that the oldest star in the universe is about 13 billion years old. So their universe is just a little bit older than the stars. Fantastic. If we'd done it and counted it the other way around and said that the stars were older than the universe, we would say science was in deep trouble. But it's not. Everything fits together and we know how the universe began. We got to know how the way it is. The future, that old suspects, we don't know quite well what's going on. But we got some ideas, which are as good as those ideas we had 40 years ago, and how big bang happened.