8 ms·
As I understand it, one suggested "double planet" definition was that the barycenter would have to be outside both objects. Earth-Moon doesn't (quite) satisfy t
by pdonis 16d ago
As I understand it, one suggested "double planet" definition was that the barycenter would have to be outside both objects. Earth-Moon doesn't (quite) satisfy that condition, but for example, Pluto-Charon does.
- nephihaha 16d agoThe Earth-Moon system is certainly anomalous within our Solar System. There is no such equivalent among the three other rocky planets, and while there are large moons around the other planets, the planets themselves are far larger.
- pdonis 13d agoI assume you're not including Pluto-Charon here (presumably since Pluto is now demoted to "dwarf planet")? Their mass ratio is only about 8:1, which is far smaller than Earth-Moon, 81:1.