Photo by Paul Sveda

by Ross Diener

The introductory panel discussion for the Q2C festival was held last night. Nine well-respected physicists, Katherine Freese, Leo Kadanoff, Lawrence Krauss, Neil Turok, Sean M. Carroll, Anton Zeilinger, Gino Segrè, Andrew White and David Tong were invited to discuss theoretical physics for a general audience at the Perimeter institute, and also for viewers who watched the live stream on this website. The theme of the entire Q2C festival is “Ideas for the Future,” and I think that the introductory panel discussion certainly adhered to this theme.

Neil Turok, the director of the Perimeter Institute, gave a quick introduction of the festival. He spoke about the power of theoretical physics historically: how it has improved our daily lives and also how it has improved our understanding of the world. We wouldn’t have radio waves, lasers, GPS without physics, but we also wouldn’t know that our planet was travelling through space at 30 km/s at the edge of the Milky Way galaxy. It is important to remind folks that physics has helped mankind, but Dr. Turok was also sure to emphasize the power it will have in the future to help solve crises facing the world, like a global energy crisis for example, or to further our fundamental understanding, say, of the brain. Science is closely related to the big issues that the world will face in the future.

Each of the panellists was asked, “What questions about physics keep you up a night?” I am going to undemocratically talk about only a couple of physicists’ answers, mostly those responses that tie in nicely with the “ideas for the future” theme. The answer that Lawrence Krauss gave to the above question was, “Have we reached the limits of empirical science?” He is concerned because he knows that there are interesting experiments about to start up, like the Large Hadron Collider, where we should find exciting new physics, but there could be one big problem: these experiments might not find anything! (To learn more check out the Q2C event Science in the Pub: The Biggest Gamble in Physics Tuesday Oct 20, 2009 @ 7:00 pm.)

Also, if you remember my discussion of the multiverse , we might be in one unique universe, and there could be any number of other universes. The problem with the multiverse is that it is quite controversial whether we would ever be able to even glimpse the other universes out there. So we might find nothing at all from our newest and most expensive experiments, and there might be other universes with different physics that we will never be able to see. Our understanding of physics could be reaching the limits of feasible experiments, with information out there that we are simply incapable of observing. If this is true, then physics would have to be done differently in the future, and it would rely very heavily on theorists, like the researchers at the Perimeter Institute. But experiments are crucial to science, so you can see why Lawrence Krauss might lose sleep thinking about the limits of experimental physics. 

 Anton Zeilinger had a similar thought. He wonders, “How far are we along the road?” What he means is, how much physics do we really understand? How much more physics is out there to be discovered? Have we just scratched the surface, or have we nearly come to understand it all. He stated that science is only half a millennium old, so it was only a short while ago that we even had the guts to ask, “Nature, what will you do?” And even less time has passed since we thought of making laws to describe what nature will do. Could we possibly be close to a set of laws that will describe everything? To really get a feel for this question, we should take a look at what keeps Gino Segrè up at night.

Photo by Paul Sveda

Gino said that he stays up at night trying to think of crazy ideas. Why? He first noted that Newton was 25 years old when he came up with his laws of motion. Einstein was 25 when he came up with special relativity, Heisenberg was 23 when he came up with matrix mechanics, and Dirac was 25 when he came up with Dirac equation. They all had these revolutionary ideas when they were young and crazy, and the age cut-off is around 25. (This means I have less than four years to come up with my own revolutionary idea.) The age of these physicists is not really important, but the fact that they had revolutionary ideas certainly is. However there is a theme to most of these revolutionary ideas, and that is the idea of unification.

Newton was the first unifier, and I heard it put very nicely last night that when he earth when he proposed his laws of motion and gravity, he unified the motion of heavenly bodies with the motion of objects on. Einstein was another great unifier. He unified space and time, and the main insight of Einstein’s relativity is that space and time cannot be thought of as separate from each other. Maxwell unified electricity and magnetism into electrodynamics, which just so happens to be nicely unified with special relativity. Heisenberg and Schrodinger unified particles and waves when they came up with quantum mechanics, and Dirac unified quantum mechanics with (special) relativity. Feynman, Schwinger and Tomonaga shared a Nobel Prize for unifying quantum mechanics, special relativity and electrodynamics, and then Weinberg, Salam and Glashow won one for unifying the weak force with quantum electrodynamics. Even if you don’t know what half of those terms mean you can see that there is a clear pattern here. 

Photo by Paul Sveda

There is a lot of unification going on, and you might think that everything has been unified. Almost. There are four fundamental forces, named the strong force, the weak force, electromagnetic force and gravity. We already saw that the weak force and electromagnetic force have been unified, and there is some interesting evidence that indicates that we can, and should further unify these two with the strong force. Theories with the strong, weak and electromagnetic force all unified are called grand unified theories (GUTs.) With a GUT you might say that we are nearly done our job of unifying all of physics. All we need to do is throw gravity into the picture somehow. But things get very tricky at this point, and it seems like we need a 25-year-old physicists with a revolutionary idea to tie this last knot, if it is the last knot. Nonetheless, it is not unjust or arrogant for a physicist to wonder if we are close to a theory of everything, but we could be miles away. It is the kind of thing that might keep you up a night. If you ever take a walk through the Perimeter Institute late at night you will certainly see insomniac physicists trying to tackle the problem.

This entry was posted on Friday, October 16th, 2009 at 6:15 pm and is filed under Q2C Panels and lectures, Uncategorized. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.