'String theory' is new dimension

During the late 20th century, "much of the public considered physics kind of nutty," conceded Richard H. Price, University of Utah physics professor. "Now physicists consider physics kind of nutty."

Price's comments came last week when he introduced Gary T. Horowitz, professor of physics at the University of California, Santa Barbara. During his public lecture, Horowitz touched on many strange aspects of modern physics.

But the most far-out idea — and the most revolutionary — is a yet-unproven notion called string theory.

Other areas of physics that eventually proved true reached far beyond our "common-sense" notions of what the world is like, such as the fact that no matter what forces are involved, nothing can go faster than the speed of light.

They are tame compared to string theory.

Imagine a world of 10 dimensions.

Or multiple universes co-existing with our own. These are among the most unusual aspects of the theory.

It's such a burgeoning field of research that a weeklong conference on string theory and mathematics will be held at Snowbird Resort next June. Sponsors include the U.

Based on Horowitz's talk and on telephone interviews with two string theorists at the U., here is a primer on string theory. The U. experts are Katrin Becker, assistant professor, and Yong-Shi Wu, professor, both in the department of physics.

When we examine solid material on a small scale, Horowitz said, we find it is made of atoms that are mostly empty space. They are dense nuclei surrounded by clouds of electrons. The nuclei are made of protons and neutrons.

These turn out to be made of smaller particles with different properties. They seem to be point-like, not sizeable chunks of material.

String theory holds that if we could enlarge the particles enough, we would find that they are actually not point-like but single-dimensional objects that are like "little loops of string," Horowitz said. The strings can vibrate in many ways. "The idea is that the different particles we can see correspond simply to different modes of vibration of these little strings."

If a string vibrates one way, we perceive it as one kind of subatomic particle. If it vibrates in another style, it is a different type. Strings can interact by splitting into two loops, or two loops joining to form one.