The great String Theory debate: Brian Greene and Lawrence Krauss

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 ( 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.