Forget About T-back If We have G-String

It’s not only the T-back (turn-back as explained by her method of chalk and blackboard reasearch) that is a woman thing but as well as the Gravitational String as Lisa Randall explains it in an Interview with Discover Magazine

What is so special about gravity?

In string theory there are two types of strings, open ones with ends and closed ones that loop around. Open strings are anchored to the surface of a brane, so the particles associated with them are stuck on the brane. If you have an open string associated with the electron, for example, it’s on a brane. Gravity is associated with a closed string. It has no end, and there is no mechanism for confining it to a brane. Gravity can spread out anywhere, so it really is different. It can leak out a little into extra dimensions. That can explain why gravity is so weak compared with the other forces. After all, a little magnet can lift a paper clip against the pull of the entire Earth.

Some of these ideas sound, frankly, a bit crazy to the average person. Where do they come from?

One reason people think about extra dimensions is string theory, the hypothesis that fundamental particles are actually oscillations of tiny strands of energy. String theory gives you a way to combine two very different models of the world, quantum mechanics and general relativity. Basically, quantum mechanics applies on atomic scales, and general relativity applies on big scales. We believe there should be a single theory that works over all regimes. String theory does that, but only in a universe that has more than three dimensions of space. More generally, there’s stuff we don’t understand if there are only three dimensions of space, and some of those questions seem to have answers if there are extra dimensions. Also, no fundamental physical theory singles out three dimensions of space. The theory of gravity allows any number. So it’s logical to think what the world would look like if extra dimensions are there.

How will we know if your ideas are right?

Experimentalists will look for what are called Kaluza-Klein particles, which are associated with the hidden dimensions. The Large Hadron Collider [a particle accelerator on the French-Swiss border that will switch on in 2007] could have enough energy to produce these particles. In our theory, Kaluza-Klein particles will decay in the detector—you find the decayed product and you can reconstruct what was there. That would provide very strong evidence of extra dimensions. Maybe within five years we’ll know the answers.

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