Sorry. I should have searched for this question before asking it again. Don't know how to delete this thread.
That said, I have a question relating one of the answers, which is to distinguish between actual and virtual gravitons. Supposedly, virtual particles can travel faster than the speed of light as long as they do not violate Heisenberg's uncertainty principle. This raises two further questions:
1) Does it make sense to say that a virtual particle travels faster than light, or rather that it in some sense tunnels from one location to another location without having to have moved between them?
2) If virtual particles travel faster than light (all travel faster? some travel faster? infinite speed?), then by moving a source of virtual particles back and forth should change the direction of the force felt by another particle faster than light, which would imply sending information faster than light. Or is this prevented by having the sideways movement of the emitter (at less than light speed) cause a change in direction of the resulting force to be too small to measure given Heisenberg's uncertainty principle?