Genius comment on /.

As part of a psychological experiment, two single men, a physicist and mathematician, were placed in an otherwise empty room with a beautiful naked women at the far end.

They were instructed that they'd be allowed to close half the distance to the women every 10 minutes. Disgusted at the obvious subterfuge, the mathematician walked away in disgust. But the physicist stayed behind, occasionally glancing at his watch.

The experimenters looked puzzled, then asked the physicist, "You do realize, of course, that mathematically speaking, you can never actually reach the woman?"

"Naturally", replied the physician, looking up. "But I can sure get close enough for all practical purposes!"

• 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.

A prepared a playlist of videos speaking about time travel. Most of them play around Einstein's theory of relativity, I tried to reduce them to the what seemed to be the most reliable (there's a lot of trash about the topic).