The Roche Limit is the distance from a larger celestial body beyond which a smaller celestial body will disintegrate due to tidal forces. This is because the gravitational forces of the larger body are stronger than the gravitational forces holding the smaller body together.

The Roche Limit is determined by the masses, densities, and distance between the two celestial bodies. The more massive the larger body, the denser the smaller body, and the closer the two bodies are, the smaller the Roche Limit will be.

If a celestial body crosses the Roche Limit, it will be torn apart by the tidal forces of the larger celestial body. This is because the gravitational forces of the larger body are stronger than the gravitational forces holding the smaller body together.

Phobos, Enceladus, and Europa are all moons that have crossed the Roche Limit of their respective planets. Phobos is slowly spiraling inward towards Mars and is expected to eventually be torn apart by tidal forces. Enceladus is thought to have a subsurface ocean that is heated by tidal forces, which may make it a habitable environment for life. Europa is also thought to have a subsurface ocean, and is one of the most promising places in the solar system to search for life.

The Roche Limit has implications for a variety of astrophysical phenomena. It can help us understand the formation of planetary rings, the evolution of binary star systems, and the limits of habitability in planetary systems.