The speed of gravity

[Ringo]

I've been wondering - how fast do gravity waves travel?

By that, I mean, if the sun were to vanish somehow instantaneously, it would take us 9 minutes or so to actually notice, since the light waves take 9 minutes to reach us. But what would the gravitational effect be?

Would it take the earth 9 minutes to "break orbit", or would we break free the second the sun vanished?

Ringo