The Roche limit is the minimum distance from a planet or other massive body that a smaller satellite or moon can orbit without being torn apart by tidal forces. Inside this limit, the gravitational pull on the satellite’s near side is significantly stronger than on its far side, creating stresses that can overcome the satellite’s own gravity.
If a satellite composed of loose material (like a rubble pile) crosses the Roche limit, it can disintegrate and form a ring system around the planet—like Saturn’s rings, which are believed to lie within Saturn’s Roche limit.
The Roche limit depends on:
- The densities of both the planet and the satellite
- The strength and cohesion of the satellite (rigid bodies can survive closer than fluid ones)
Understanding the Roche limit is crucial in planetary science, especially when studying the formation of ring systems, moon stability, and the dynamics of tidal disruption events near large celestial bodies.