Me: I know that this is going to seem like a dumb question, but a friend and I couldn't decide it: If the sun were to instantly disappear (that's the dumb part), would the Earth instantly fly off in a tangent to its orbit, or would it takes 8 minutes before it flew off in a tangent?

Krauss: That's not a dumb question at all!  We ask stuff like that all the time.

M: 'Cause it seemed to us that if it flew off instantly, then gravity would be faster than light.  But if it took 8 minutes, then it's a particle of somesort, and therefore a wave.  Waves have troughs as well as peaks, so the Earth should oscillate a little bit in gravity/anti-gravity ripples.  Which means that there's anti-gravity.

K: Very good!  And that would be true, except that for that to happen, gravitons would have to have spin 2, and gravitons only come in spin 1.

M: Of course!  I don't know what I was thinking.
(as my head goes into spins greater than 2!)