The force that keeps the planets in orbit around the sun is known as gravitational force, a fundamental force of nature described by Newton's law of universal gravitation. This force is dependent on the masses of the celestial bodies and the distance between them. The sun, possessing a substantial mass, exerts a gravitational pull that keeps the planets, including Earth, in stable orbits. Gravitational force is essential not only for planetary motion but also plays a crucial role in the formation and dynamics of galaxies and other astronomical structures.