What force keeps planets in orbit around the Sun?

The force that keeps planets in orbit around the Sun is gravity.

The Sun’s enormous mass creates a gravitational attraction that continually pulls each planet toward it. A planet’s sideways velocity makes it move forward, while gravity bends that path inward, producing an orbit rather than a straight-line escape or a direct fall into the Sun. Planetary orbits are generally elliptical, not perfect circles.

Isaac Newton’s law of universal gravitation describes the attraction between masses: it grows with the product of their masses and weakens with the square of the distance between them. In 1915, Albert Einstein’s general theory of relativity gave a deeper description in which mass and energy curve spacetime, but Newton’s model remains highly accurate for many Solar System calculations.

Gravity is not just a one-way force from the Sun. Planets also pull on the Sun, so both bodies orbit their shared center of mass, or barycenter. The Sun’s gravity also governs comets, asteroids, moons, and artificial spacecraft, although other bodies can perturb their paths.