Although the Moon is often described as revolving around the Earth, this is slightly inaccurate: the Earth and the Moon ''both'' revolve around their ''barycenter'', their common [[centroid|center of mass]]. This point is 1,700 below the earth's surface, which is about 1/4 of the earth's [[radius]].<ref> The radius of the Earth is 6,378 kilometers, so that means that the barycenter is located INSIDE the Earth about 1707 kilometers below its surface. [http://www.astronomycafe.net/qadir/q665.html] </ref> | Although the Moon is often described as revolving around the Earth, this is slightly inaccurate: the Earth and the Moon ''both'' revolve around their ''barycenter'', their common [[centroid|center of mass]]. This point is 1,700 below the earth's surface, which is about 1/4 of the earth's [[radius]].<ref> The radius of the Earth is 6,378 kilometers, so that means that the barycenter is located INSIDE the Earth about 1707 kilometers below its surface. [http://www.astronomycafe.net/qadir/q665.html] </ref> |