Elegant Universe Airs Tonight on PBS

fatarfy writes "USA Today among others has an article discussing tonight's presentation of Brian Greene's Elegant Universe, which discusses String Theory. It airs on PBS. From the article: 'The two segments of the show turn their spotlights on a crisis in physics, one invisible to the general public but increasingly embarrassing to the discipline. Simply put, Einstein's unbelievably accurate explanation of gravity, known as general relativity, is completely out of whack with the equally accurate explanation of electromagnetism, radioactivity and atomic forces known as quantum mechanics. The theories are mankind's most fundamental views of verifiable reality, and the disagreement means that something important about the universe eludes our understanding.' Sounds like it's worth watching."

Comments

classical/statistical - quantum reconciliation

[Doc Ruby]

At least one physicist, Garnet Ord, has extended the classical/statistical physical model of phenomena to include quantum mechanics. Perhaps similar work with Relativity can produce a grand reconciliation?

String Theory

[Academy Girl]

The thing I find funny about critics of string theory is their objection to the idea that there can be multiple dimensions beyond the three dimensions people can perceive. This is where philosophy and physics should intersect -- right at Kant, who pointed out that you cannot understand the world, only your perception of the world. Now, whether or not you agree with Kant, the point is that you, at least, shouldn't be limited by your perception of the universe. It seems plainly obvious that just because people can only perceive three dimensions, the universe certainly doesn't have to be contained by that premise.

Re:String Theory

[jazman_777]

In order to be taken seriously -- indeed, to even be considered scientific -- a physical theory should be falsifiable.

Unless, of course, it happens to be _true_.

Re:String Theory

[Bootsy Collins]

I heard Greene on NPR's Science Friday He says that some recent work on the theory predicts some effects which may be testable in a few years by the newest generation of "atom smashers" currently under construction at CERN and elsewhere.
We may get to that "falsifiable" stage relatively soon...

Unfortunately, I'm not so optimistic. At least, not in general.

To explain why . . .in string theories, one of the things that has to be explained can be oversimplistically described as "where are all the other spatial dimensions now?" Why are three spatial dimensions macroscopic (effectively, observable by us) and all the others not? In the very early universe/at extremely high energies, all the dimensions should have been equal; but somehow, three of them expanded into the universe we know while the others stayed small. How this is done mathematically is referred to as "compactification" (and for anyone out there who's a math graduate, it's the same compactification of manifolds as you encountered in topology).

Some string theories have, as a result of the compactification, one of the compactified dimensions actually being comparatively large, with a characteristic scale of about a millimeter or a micron or something like that. These "one large dimension" models look like they would have observable consequences for experiments at accessible particle accelerator energies; and so it's possible that such models could be falsified. But that's not the same as falsifying string theory; it's only the possibility of falsifying a class of models within string theory.

Re:I'm busy tonight

[NanoGator]

"Some record it and put it on Kazaa for me."

If the television industry were to be a little more forward thinking, they'd do that themselves. They'd put a few commercials in, get paid for it, and it'd be distributed virtually for free. If they maintain a server to make those shows availble with a decent download rate, then they can pretty much insure that nobody's going to edit out the commercials. (If they wanted to be real assholes, they could use Microsoft's Media format and disable indexing on it, thus meaning you can't skip commercials.)

embarassing?

[TwistedGreen]

The two segments of the show turn their spotlights on a crisis in physics, one invisible to the general public but increasingly embarrassing to the discipline... general relativity is completely out of whack with the equally accurate explanation... known as quantum mechanics.

How is this an embarassment? It's a fascinating puzzle to have uncovered! Once we nix this dilemma, we'll have the most comprehensive understanding of the physical universe ever before achieved! But it's embarassing that we've already gotten this far? Whomever thinks that does not have an accurate understanding of the nature of science.

"equally accurate"

[Bootsy Collins]

It's unfortunate that the article describes GR and QM as being "equally accurate." Presumably that helps dramatize the conflict -- if they're equally accurate, there's no reason to decide whether one of them is a better approximation of reality than the other. That helps the "crisis," as they call it, seem more like a crisis.

But in actuality, of our theories of the four forces, GR is the least well-tested of the four. It seems particularly inappropriate to compare the accuracy of predictions of GR to those of QM, since the predictions of QM have been tested to many more decimal places than those of GR (I think the theoretical prediction of the Lamb shift has been confirmed to something like 8 significant figures now). That's not indicative of a flaw in GR at all -- it merely reflects the fact that doing experimental/observational studies of gravity are really, really hard. But since GR hasn't been examined as well, we can't say that its predictions are equally accurate.

Re:book; better book

[Curtman]

I don't think TV is a great media for exploring a subject, so much as it is great for presenting you with an overview of what something is about. I've tried many times to read physics books and tire of them pretty quickly because I don't understand some underlying principle. I need lots of pictures and naration to handle these concepts. Thanks for the suggested reading, I think this series will be enough of a snapshot to prompt me to pick one of these books up and actually get through it.

Re:book; better book

[MysticGlyph]

I also have read extensivly on the subject of string theory. I found the PBS program to be VERY helpful in laying out difficult to understand concepts and actually making things understandable to the laymen, or armchair (wannabe) physicist. Another great source for string theory information is at http//www.mkaku.org ...and Michio Kaku's book "Hyperspace" is a fun and informative read, I highly suggest it for anyone interested in learning more about string theory.