Still, I was really running behind with preparing the talk. The problem was when I realized I actually had time to talk about whatever I wanted, I could not decide on what to talk about. Then I recalled what I found the most exciting when I was a student were not all the things that were known, but the open problems that were left for us to explore. So I thought, instead of talking about all the things we know I would - somewhat unusual for a scientific talk - focus on what we don't know, and where the frontiers of our knowledge currently are. Thus, the title of the talk
Frontiers of our Knowledge
Abstract: Theoretical and experimental physics work hand in hand to broaden our understanding about the universe that we live in and man's place in the world. In the 21st century, nature has given us quite some puzzles to solve, in the microscopic (particle physics) as well as in the macroscopic (cosmology) range. These open questions at the threshold of the unknown have lead theoretical physicists to formulate possible solutions whose experimental tests are awaited soon. I will talk about these current limits to our knowledge, and about the insights that new experiments like the Large Hadron Collider can provide us with. A central point will be the possibility of large extra dimensions and black hole production at the LHC.
If you want to classify my current state of mind, I'd say I'm an high energy physicist trying to become a cosmologist. I think that in the soon future more interests will shift from particle physics towards cosmology, which right now I find a tremendously exciting area. So in my talk I wanted to talk about both, cosmology and particle physics, especially also the areas where they overlap e.g. dark matter searches, and what that has to do with the 'big' questions like: Where do we come from? What are we made of? (Why am I spending my Saturday at work?)
Well, at least that was the idea. But I have never before given a talk about cosmology (I don't even know what an 'erg' is. Luckily, nobody asked.) I was really kind of nervous (in addition you should know that this lecture starts at 10am, and I didn't have any coffee because due to some problem with the key cards I couldn't get into my office.)
PI's public outreach program is organized by Damian Pope, who told me the format is rather casual, and the physics knowledge of the audience often pretty mixed. So I thought the best would be not to use too many equations, but to really explain every detail (be honest, usually you don't do that since everybody has seen this figure a million times). Bruno made a very nice introduction, and I looked at the large seminar room getting fuller with people. You're not going to believe it, but soon all seats were taken. In fact, after 15 minutes, Damian asked me to interrupt my talk so we could change into the big lecture hall. As I said to Bruno: I think I'm in the wrong movie.
As you can guess, my timing for the talk was a complete disaster. I had to skip the biggest part of the second half, and I had to promise I would put the slides online, so here they are:
Frontiers of our Knowledge (Powerpoint Presentation, ~20 MB)
I am afraid the size of the file is rather large because it has a lot of photos. I have thrown out the movies that I showed, you can download them here:
I believe in recycling, so part of what I told today is based on posts I have written here, in particular Dark Matter, The World's Largest Microscope, Anomalous Alignments in the Cosmic Microwave Background (piecewise), Micro Black Holes and Extra Dimensions.
People had a lot of questions. The best question was without doubt: Do you know what caused the big bang? It was a good question, because it didn't ask what caused it, but if I know it. It happens only rarely that I can clearly answer a question with yes or, in this case, with no.
If I find the time, I will write a summary of the talk sometime next week, if you will find it, then you will find it here.
Overall seen, giving the lecture was a great experience. In fact, I volunteered to do it again...