THEORY OF EVERYTHING

EINSTEIN'S DREAM THEORY OF EVERYTHING

NEW YORK – Einstein died before completing his dream of creating a unified theory of everything. Since then, physicists have carried on his torch, continuing the quest for one theory to rule them all.

Many physicists say our best hope for a theory of everything is superstring theory, based on the idea that subatomic particles are actually teensy tiny loops of vibrating string. When filtered through the lens of string theory, general relativity and quantum mechanics can be made to get along.

For that reason, string theory has inspired many physicists to devote their careers to developing it since the idea was first proposed in the 1980s.

But other experts are getting weary of string theory, which has yet to produce concrete, testable predictions. Perhaps string theory, and the whole idea that a single theory can explain the universe, is misguided, they say.

One aspect of string theory that riles many is that many versions of it require the universe to contain more than the three dimensions of space and one of time that we are familiar with.

The most popular version of string theory, in fact, calls for 11 total dimensions.

"Why don't we see them?" Levin said. "It might be that they're very, very small. Or it might be that we are somehow confined to a three-dimensional kind of membrane. Or it might be that they're not there. But these are very interesting ideas that have some very compelling consequences."

Luckily, the question of higher dimensions isn't entirely restricted to the theoretical domain. There is some hope that experiments such as the Large Hadron Collider – the world's most powerful particle accelerator in Geneva, Switzerland – will be able to provide experimental evidence of hidden dimensions in the universe.

The evidence may be in the absence of certain particles, or missing energy, that might result when a particle leaves our normal dimensions and enters one of the hidden ones.