Answer to Question #56918 in Astronomy | Astrophysics for Muhammad Umer

Question

Newton's derived his law of universal gravitation by considering moon and earth , so why we use his law everywhere ?

Answer 1

Newton's derived his law of universal gravitation without making any assumptions about the objects that satisfy it. Such objects must have only one physical characteristic – mass. That’s why his theory can be applied to any massive object in the Universe.