Definition of Roche limit in English:

Roche limit

(also Roche's limit)


  • The distance within which the gravitational field of a large body is strong enough to prevent any smaller body from being held together by gravity.

    • ‘A collision which would have ejected material less than the Roche limit would have formed only rings around the earth.’
    • ‘At a certain distance near a planet, known as the Roche limit, an object can be literally pulled apart by gravity.’
    • ‘Phobos has a number of interesting surface features, including grooves that could be created by the gravity gradient of Mars - Phobos is within Mars's Roche limit - trying to tear the moon apart.’
    • ‘The magic distance, within which a planet's tidal force exceeds the gravity holding together that kind of vagabond, is called the Roche limit - discovered by the nineteenth-century French astronomer Edouard Albert Roche.’
    • ‘Amalthea is not a rigid body, being inside the Roche limit; but its gravity is more than adequate to hold it together, being 6 times stronger than the forces pulling it apart.’


Late 19th century: named after Edouard Albert Roche (1820–83), French mathematician.


Roche limit