Science question: Does gravity propagate faster than the speed of light ?

I recall hearing an episode of Coast long ago w/some science guest.

He said the speed of gravity, which they measure by seeing how quickly celestial bodies act upon each other is pretty much instant.

So if you could somehow travel at the speed of gravity you could probably traverse the universe. I also recall him saying something about how you might create a mini-black hole in front of your craft pulling it towards it kinda like a carrot on a stick/donkey.

reply to post by muggl3z


Hmm. It looks as if everyone is pretty well divided on this. I say it is a ripe area for exploration!

Something else that came up in my forays on the INet, mass can be converted to energy, but the reverse is not possible without intelligence. Very curious, I will study this further.

reply to post by ALLis0NE


I understand your argument. However, since Einsteinian Gravity is a curvature of Space-Time caused by mass, wouldn't it take some amount of time for the curvature of Space-Time to return to 'neutral' after the Sun winks out?

Consider the popular image of a tautly stretched rubber sheet with a bowling ball a causing a 'dimple' in the sheet. Remove the bowling ball and the sheet returns to its flat state. But that return to flat takes some definite length of time.

So my answer is that however long it takes, the Earth would experience a gradually diminishing gravitational effect from the Sun as Space time 'settled down'.

That rubber sheet image might even be more apt than otherwise expected, because I don't see any reason why the 'fabric' of Space-Time wouldn't oscillate for a time before returning to 'steady-state'. (Actually yes I do, it would require the 'fabric' of Space Time' to possess inertia, and that doesn't seem reasonable to me for some reason. Its been a very lllloooonnnngggg time since I've thought about this stuff in any depth).

At any rate I expect it wouldn't be a smooth ride for the Earth.