The Limits of Time

In quantum gravity, there are several programs of research. The one that I have worked in and most identified with is loop quantum gravity. This was a form developed by Ashtikar and before him, although we didn't know about this by Plubanski. And this is now a big research program. We have every two years an international conference. It's very close to Yang-Mills theory. They're very close to gauge theory. So let me discuss each of those in turn.