The great String Theory debate: Brian Greene and Lawrence Krauss
- Download MP3(105 MB)
- Download OGG (52 MB)
Wed., March 28, 7 p.m.
It comes down to this: Are all things in nature actually super-tiny bits of strings that are vibrating strands of energy? If so, string theory would merge general relativity and quantum mechanics, and would explain the origin of space, time, and the universe itself. Or is the theory, as some critics claim, just extraordinarily complex mathematics which may have nothing to do with physics and a theory of nothing, not everything? If so, physicists are back to the drawing board in their quest for the Holy Grail of physics'an ultimate theory of everything.
Lawrence Krauss and Brian Greene, two world-renowned physicists, square off in a spirited debate and discussion moderated by noted cosmologist Michael Turner. Greene's research focuses on superstring theory, which proposes a quantum theory of gravity as well as a unified theory of all forces and matter. This requires that the universe have 10 or 11 dimensions, not just the 4 we're aware of.
Krauss works at the boundary of particle physics and astrophysics, cosmology, and general relativity. His research deals with black holes, the very early universe, the future of the universe, dark matter, and dark energy. He is sceptical about string theory because it has yet to make a prediction that can be verified by experiment and has not solved any major physical puzzles about nature, including why the expansion of the universe is speeding up, the most profound question of our time.
Greene is a professor of physics and professor of mathematics at Columbia University; Krauss is Ambrose Swasey professor of physics and a professor of astronomy at Case Western Reserve University; and Turner is the Rauner Distinguished Service professor in the Kavli Institute for Cosmological Physics at the University of Chicago.
The Dept. of Energy's Office of Science (www.science.doe.gov) is the United States' largest supporter of basic research in the physical sciences.
I took the audio from HoodedHawk (thanks!), merged, polished and uploaded to the archive.
1 comment so far:
Andrew Sealy-Bell (not verified) says: Response to Debate
First of all, it's always nice to see a debate held in the type of spirit that Lawrence Krauss and Brian Greene seem to generate. Although they have differing opinions it's always entertaining to listen to their banter.
I tend to agree with a comment that Steven Weinberg made on string theory (and I know that Lawrence Krauss has a great deal of respect for him). He basically said that the theory is so mathematically 'beautiful' that he feels there will be some aspect of string theory which is correct. This is how I feel about it although I also have another issue with it. Don't get me wrong, I would love to believe that string theory is the - or on the right path - to a unified theory of everything. However, something else that Steven Weinberg said also made me think - he said that there are many mathematically consistent models which DO NOT describe the real world. Very beautiful mathematics which if taken alone would be tempting to believe were real but in fact were proven not to describe the real world through actual experiments.
I agree with Brian Greene on the point that it's not 30 or 40 or 50 years of theory without experimental proof that is a problem, as Lawrence Krauss seems to think. If you are working on such a profound theory as string theory then yes, I think it would naturally take a long time to see results. It also seems an obvious point that the scales we are talking about are so incredibly tiny that our current technology cannot detect these particles.
Even if string theory turns out to be 'wrong' then i'm sure all the work wouldn't have been wasted - it would have led scientists to think about other related ideas and investigate them in more detail they they perhaps would have done otherwise.
Let's see if the LHC detects super-symmetry and possibly the graviton. Wouldn't it be exciting to detect a graviton and then 'see' - well, not see it - but detect it disappearing into another dimension? by measuring the energy before and during the impact and then after. If the graviton disappears - or the energy from it, then where did it go? if the theory is correct and gravitons can in fact move freely between dimensions (due to it's string vibration 'shape' - I think 'closed') then it would both prove that other dimensions exist and could also explain why gravity is so weak compared to the other fundamental forces of nature.
Regards,
Andrew.
Post new comment