Roche limit

[ rohsh; French rawsh ]
/ roʊʃ; French rɔʃ /

noun Astronomy.

the minimum distance below which a moon orbiting a celestial body would be disrupted by tidal forces or below which a moon would not have formed.

Origin of Roche limit

1885–90; named after French astronomer Édouard Roche (1820–83), who first calculated it

British Dictionary definitions for roche limit

Roche limit
/ (rɒʃ) /

noun

astronomy the distance from the centre of a body, such as a planet, at which the tidal forces are stronger than the mutual gravitational attraction between two adjacent orbiting objects

Word Origin for Roche limit

C19: named after E. A. Roche (1820–83), French mathematician

Scientific definitions for roche limit

Roche limit
[ rōsh ]

The shortest distance at which a satellite not held together by any force other than its own gravity can orbit another celestial body without being torn apart by the tidal force between them. The distance depends on the densities of the two bodies and the orbit of the satellite. If the satellite and the object are of similar densities, the Roche limit is about two and a half times the radius of the larger object. Since most natural satellites are rigid bodies, their tensile strength allows them to orbit much closer than their Roche limit; however, rigid bodies too may be broken up by tidal forces. The rings surrounding Saturn and the other gas giants in the outer solar system may be the orbiting debris of moons that approached much closer than the Roche limit and were fragmented by tidal forces. The limit is named after the French mathematician Edouard Roche (1820-83).