Changes in gravity are transmitted instantaneously across any distance.

Newton’s law of gravity was extraordinarily successful. It explained falling objects, planetary orbits, tides, and much more.

But its mathematics contained an uncomfortable feature. The gravitational pull between two masses depended on where they were at the same instant. Taken literally, if one mass changed position, the effect could be felt arbitrarily far away with no travel time.

Newton himself was uneasy about unexplained action at a distance, although his equations worked extremely well for ordinary astronomy.

General relativity changed the underlying picture. Gravity was no longer treated as a force reaching instantly across empty space. Mass and energy affect the geometry of spacetime, and changes in that geometry propagate outward at the speed of light.

When massive objects accelerate strongly, those changes can travel as gravitational waves: ripples in spacetime that carry information about the motion that produced them.

Direct detections of gravitational waves beginning in 2015 provided observations of such traveling disturbances.

This does not mean a static gravitational field should be imagined as a stream of new signals constantly leaving a stationary mass. The finite-speed rule concerns changes and causal influences. Newtonian gravity remains an excellent approximation when speeds are low and gravitational fields are weak.