3 ms·
The barycenter of the Earth-Luna system is (currently) entirely within the Earth. So Luna is a moon. Once it's outside the radius of Earth, then it'd be a doubl
by SAI_Peregrinus 3y ago
The barycenter of the Earth-Luna system is (currently) entirely within the Earth. So Luna is a moon. Once it's outside the radius of Earth, then it'd be a double-planet system (or a double dwarf-planet system if that nomenclature lasts).