The force that attracts objects toward the center of the Earth is called gravity. Gravity is a fundamental force of nature that pulls objects with mass toward one another. It is this force that gives weight to physical objects and is responsible for the downward motion when an object is dropped. Sir Isaac Newton formulated the universal law of gravitation, which describes the gravitational attraction between two masses as proportional to their masses and inversely proportional to the square of the distance between them. Gravity keeps planets in orbit around the sun and holds everything, including the atmosphere, close to the Earth.