Roche limit

English

Etymology

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

Noun

Roche limit (plural Roche limits)

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

   Synonym: Roche radius

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

     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.

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

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

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

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

Related terms

• Roche lobe
• Roche surface

Translations

distance of a satellite from its parent body at which its internal gravitational forces exactly balance the external tidal forces

• French: limite de Roche f
• German: Rochegrenze f
• Italian: limite di Roche m
• Russian: преде́л Ро́ша m (predél Róša)