Moons can have moons and they are called moonmoons

 作者:甘韧夺     |      日期:2019-02-27 03:01:01
NASA By Leah Crane Stars are orbited by planets, which are orbited by moons, but what comes next? More moons, according to a new analysis. Juna Kollmeier at Carnegie Observatories in Pasadena, California, and Sean Raymond at the University of Bordeaux, France calculated whether a moon orbiting a planet could have a moon of its own. A moon of a moon has no formal name, perhaps because we have never spotted one,