Roche limit

noun

The closest a satellite can approach its parent body before the gravitational forces holding it together are overwhelmed by tidal forces pulling it apart.

Meanings

nounRoche limit (plural Roche limits)

plural Roche limits

  1. astronomyThe closest a satellite can approach its parent body before the gravitational forces holding it together are overwhelmed by tidal forces pulling it apart.

    The prelunar mass must first be moved outside the Roche limit if accumulation is to occur.

    1986, William K. Hartmann, Roger J. Phillips, G. Jeffrey Taylor, editors, Origin of the Moon, Lunar and Planetary Institute, page 91
    2 more examples

    It might be argued, therefore, that Jupiter is so massive and its gravitational field so intense that it swept out the matter within its Roche limit very effectively.

    1979, Isaac Asimov, The Road to Infinity, Doubleday, page 145

    If, however, the planet's moon comes inside the Roche limit, the tidal forces overcome its gravity and pull the moon apart.

    2003, Michael A. Seeds, Foundations of Astronomy, Brooks/Cole, page 512

    Synonyms: Roche radius

Synonyms & antonyms

nounThe closest a satellite can approach its parent body before the gravitational forces holding it together are overwhelmed by tidal forces pulling it apart.

Also see

Origin

Named after French astronomer Édouard Roche, who first calculated the limit in 1848.

Full word history & related roots →

Translations

French limite de Roche
  • limite de Rochedistance of a satellite from its parent body at which its internal gravitational forces exactly balance the external tidal forces
German Rochegrenze
  • Rochegrenzedistance of a satellite from its parent body at which its internal gravitational forces exactly balance the external tidal forces
Italian limite di Roche
  • limite di Rochedistance of a satellite from its parent body at which its internal gravitational forces exactly balance the external tidal forces
Russian преде́л Ро́ша
  • преде́л Ро́ша (predél Róša)distance of a satellite from its parent body at which its internal gravitational forces exactly balance the external tidal forces
Cite this entry
APA

Roche limit. (n.d.). In WatkinsX Dictionary. Retrieved November 4, 2026, from https://dictionary.watkinsx.com/word/Roche%20limit

MLA

“Roche limit.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/Roche%20limit. Accessed November 4, 2026.

Chicago

WatkinsX Dictionary, s.v. “Roche limit,” accessed November 4, 2026, https://dictionary.watkinsx.com/word/Roche%20limit.

Source: Roche limit on Wiktionary, CC BY-SA 4.0.