The force that keeps the planets in orbit around the sun is known as gravity. This fundamental force is responsible for the attraction between the sun and the planets, causing the planets to follow elliptical orbits rather than flying off into space. The strength of the gravitational force depends on the masses of the celestial bodies involved and the distance between them. This gravitational interaction is paramount for maintaining the structure of our solar system, influencing planetary movements, and enabling the dynamic balance that governs the cosmos.