Does gravity "travel"?
Gravity has an infinite range so according to the theory every object in the universe is imposing a gravitational pull on every other object, albeit imperceptibly small for the most part.
Imagine if something with enormous mass suddenly appeared maybe a light year away from us, out of thin err, space. The light from this object would take a year to travel to us but how quickly would the gravitational force of that object begin to have an effect on the planet?