An Etymological Dictionary of Astronomy and Astrophysics
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فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 1 Search : Cassini''s law
Cassini's law
  قانون ِ کاسینی   
qânun-e Cassini

Fr.: loi de Cassini   

Any of the three empirical laws governing the rotational dynamics of the → Moon:
1) The Moon rotates uniformly about its polar axis with a → rotational period equal to the mean → sidereal period of its orbit about the Earth.
2) The → inclination of the Moon's equator to the → ecliptic is a constant angle approximately 1.5°.
3) The → ascending node of the lunar orbit on the ecliptic coincides with the → descending node of the lunar equator on the ecliptic. This law could also be expressed as: the spin axis and the normals to the ecliptic and orbit plane remain coplanar (Noyelles, 2009, Icarus, 202, 225).

Named after Jean-Dominique Cassini (1625-1712), French astronomer of Italian origin, who established these laws in 1693 (Traité de l'origine et du progrès de l'astronomie), ; → law.