How universal is Newton’s Law of Universal Gravitation? We already know that this law does not apply when the gravitational force is very strong (like near a black hole). And when the gravitational force is very weak (like between two billiard balls) we don’t really know if Newton’s Law applies or not, because such a tiny force is very difficult to measure.

Watch below for the latest Minute Physics video supported by the Foundation’s Science program, which funds fundamental research primarily in the physical sciences, including research in the precision measurement of gravity between small masses at short distances.