How do gravitons cause gravitational attraction?

[dilletante]

I can picture gravity as the warping of spacetime as postulated by GR but I have not heard a descriptive explanation of how a graviton might cause an attraction between two masses, or even if it is a cause in quantum theory. So okay, you have a closed string or a massless particle with a spin of 2 out there, but how does that cause the Earth to fall towards the sun, for example? Is it some kind of a messenger particle that, when it hits something, says in effect "come this way?" What is the function of this theoretical particle and what role does it play in gravitational attraction? All I have heard are descriptions of the particle itself, as opposed to how it acts.

 

[jtbell]

Gravitons are supposed to work for gravity similarly to the way photons work for electromagnetic interactions, the W and Z bosons work for the weak interaction, and gluons work for the strong interaction. Beyond that, we don't know much about them (or if they even exist!) because we don't have a working theory of quantum gravity yet.