单词 | roche limit |
释义 | Roche limitRoche limitR0274150 (rōsh)Roche limit(rɒʃ)Roche limitRoche limit,the closest distance that a celestial body held together only by its own gravity can come to a planet without being pulled apart by the planet's tidal (gravitational) force. This distance depends on the densities of the two bodies and the orbit of the celestial body. Inside the Roche limit, orbiting material will tend to disperse and form ringsring,in astronomy, relatively thin band of rocks and dust and ice particles that orbit around a planet in the planet's equatorial plane. All four of the giant planets in the solar system—Jupiter, Saturn, Uranus, and Neptune— have rings, although only those of Saturn ..... Click the link for more information. , while outside the limit, material will tend to amalgamate to form celestial bodies. The French mathematician and astronomer Edouard Roche first enunciated this theoretical limit in 1848. If a planet and a satellite have identical densities, then the Roche limit is 2.446 times the radius of the planet. Some satellites, both natural and artificial, can orbit within their Roche limits because they are held together by forces other than gravitation. Jupiter's moon MetisMetis Roche limit(rosh) The minimum distance from the center of a body at which a satellite can remain in equilibrium under the influence of its own gravitation and that of its primary. Assuming that the satellite is held together only by gravitational attraction, i.e. it has zero tensile strength, and that it has the same density as the primary, the Roche limit is about 2.45 times the radius of the primary. Inside the Roche limit a satellite would be torn apart by tidal forces. It is thought that the ring systems of the giant planets were formed when a satellite wandered inside the planet's Roche limit. The expression for the limit was discovered in 1849 by the French scientists Edouard Roche. |
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