Legend has it that Isaac Newton had the moment of inspiration that would lead to his theory of gravity when, on a warm afternoon, he saw an apple fall from a tree and wondered why it should fall down ...

Gravity is the force of action between two objects. It’s called a natural force because it acts at a distance rather than needing to be in contact. Gravity is the force that holds us down on Earth and ...

The geoid (the surface of equal gravitational potential of a hypothetical ocean at rest) serves as the classical reference ...

Gravity feels reliable—stable and consistent enough to count on. But reality is far stranger than our intuition. In truth, the strength of gravity varies over Earth's surface. And it is weakest ...