(Photo from here, Justin Sullivan/Getty Images)
OK, I didn't actually see him at Zellerbach hall. I was in the overflow area (Wheeler auditorium) watching on simulcast. Most of it was pretty basic Einsteinian cosmology with which I was familiar, but I did learn a few new things:
- Hawking believes that the funamental constants of the universe do not have arbitrary values, but that they can all (in theory) be derived from principles. There's no need for "God" to "seed" these values in advance to generate a universe. I knew this was a point of debate, and I didn't know which side Hawking was on
- The universe initially expanded extremely rapidly, then slowed down, but is now speeding up its expansion again, and there is no good theoretical explanation for why this is happening. (I think "Dark Energy" is the current explanation, and it has always struck me as something of a kludge.) I guess I knew this, but the weirdness of it struck me when Hawking mentioned it in his talk.
- I liked his analogy for answering the "What happened before the beginning of time?" question. His answer is that it's analogous to asking "What is south of the South Pole?". It's undefined.