Gravity

Gravity, also called gravitation, in physics, is a fundamental force that attracts two masses toward each other. It is one of the four fundamental forces of nature, the others being electromagnetism, and the strong and weak nuclear forces. Gravity is responsible for keeping the planets in orbit around the Sun, the Moon in orbit around the Earth, and for keeping our feet on the ground. The force of gravity is proportional to the product of the masses of the two objects and inversely proportional to the square of the distance between them. This is described by Newton's law of universal gravitation, which was formulated by Sir Isaac Newton in 1687. In modern physics, gravity is described by Albert Einstein's general theory of relativity, which states that gravity is the result of the curvature of spacetime by mass and energy. The term "gravity" comes from the Latin word gravitas, meaning "weight" or "heaviness". In Hebrew, gravity is called כוח הכבידה (ko'ach hakavida), in French it is gravité, in German it is Schwerkraft, and in Spanish it is gravedad.