The distance from a celestial body within which tidal forces will overcome the gravitational forces holding a smaller orbiting body together, causing it to break apart. Objects closer than the Roche limit will be torn apart by tidal forces.
Named after French mathematician Édouard Roche, who calculated this critical distance in 1848 using mathematical analysis of tidal forces. His work explained why Saturn's rings exist as particles rather than coalescing into moons.
The Roche limit explains why Saturn's spectacular rings exist - any moon-sized object venturing too close gets shredded into countless particles! This same principle means that if you could somehow bring the Moon closer to Earth than about 18,000 kilometers, it would be torn apart and Earth would develop its own ring system.
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