Quote:
Originally Posted by LeXman
A question for Astronomy Cast:
If Einstein theorized, and observations have proved, that gravity is caused by the curviture of space-time, why are particle physicists looking for gravitons?
-- LeXman
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You're under a small misunderstanding. Observations haven't proved General Relativity (GR), they just haven't disproved it. There are several other proposals for gravity that, as yet, haven't been disproved either.
Sticking here strickly with GR, the main reason for the search for gravitons, is that GR is a classical theory, in the sense that GR isn't quantizied. Under a quantum theory of gravity, gravity would be force, mediated by gravitons (much as the electromagnetic force is mediated by photons).
As for gravitons, since gravity is purely attractive, it would have to be a spin two boson. Since the effects of gravity move at c, the graviton would be massless. The questions then become does the graviton interact between mass or energy causing the appearance of curvature or does the graviton interact between spacetime (or the Higgs particle) and mass or energy, actually producing the curvature of spacetime. Those are the million dollar questions.