🚀 go-pugleaf

jac@ds8.scri.fsu.edu (Jim Carr) writes:
>>1) Is the effect of gravity instantanous?

>Probably not, but I do not think that there is any data on the question. 
>(In principle, one could measure the change in gravity when a particle 
>and anti-particle annihilate, but in practice ....

The annihilation would create photons which would have some
contribution to the stress-energy tensor, so this wouldn't really
work in principle either.  Gravitational waves (defined as small
perturbations to a background metric) propagate at the speed of
light, however.  This is a good an answer as I can give to the
original question (please, let's not get into the "speed-of-gravity" 
war again!)