Large moon of Uranus may explain odd tilt

 作者:毋铰逢     |      日期:2019-03-08 06:11:11
THE odd tilt of Uranus may be the result of it once having had an outsized moon. Uranus spins on an axis almost parallel with the plane of the solar system, rather than perpendicular to it – though why it does this nobody knows. One theory is that the tilt is the result of a collision with an Earth-sized object, but this “hasn’t succeeded in explaining much of anything”, says Ignacio Mosqueira of the SETI Institute in Mountain View, California. Why, for example, are the orbits of Uranus’s 27 known moons not also tilted?