Gravitons

[colinha]

I am told that the force of gravity is caused by the warping of space/time by mass. This seems to be fundamentally different from the other 3 forces which are due to exchange of particles such as photons. If the above is true, what is the point of looking for gravitons or trying to unify all forces in a theory of everything??

[fishy-finger]

it depends what theor you are basing this on. like are you presuming everything is made up of quarks or are you thinking of the string theory. try be a bit more detailed about the fundamentals when asking dear old boy.

[Rev. Green]

No-one knows what causes gravity. It could be just like the other forces with a graviton with spin 2, but I think there are hints that it is not: it is very weak (at our usual energy scale); it is exactly proportional to the inertia of an object, just like Coriollis force or centrifugal force.

If we understood inertia we would be closer to understanding gravity, but inertia is tricky. A body doesn't have inertia on its own, it is related to the rest of the universe.

A learned professor once told me that gravity was similar to the other forces "because there are four forces and gravity is one of them". So he didn't know either.

[fo3nix]

As far as I'm aware, gravitons could just be virtual particles.

Take phonons for example. They aren't really there. But it kind of looks as though they're there.

However, I have read about theories that gravity is just a remnant of the other 3 forces, as a kind of side effect. These are some of the things that interest me right now.

[jake-the-peg]

There is an obvious contradiction which you've clearly seen.

The point is to try to find a way to formulate Gravity in a manner more in-line with the other fundamental forces which might well give us the boost to understand Gravity in that way and hence to unify the forces.

Why do we think this should be possible?

Well we've seen it twice before.

Firstly Electricity and magnetism were thought to be seperate forces and then Maxwell formulated the equations to show how they were just aspects of the same.

Then about 20 years ago it was shown that the weak force was part of this too at very high energies.

It may be that Gravity is simply not an aspect of the other forces but that's why you look for gravitons.

Sometimes looking for something and not finding it is more important.

Michaelson and Morely were looking for the ether - they didn't find it and the consequence was special relativity