Thoughts on geocentrism

Mark Whorton (Mark.Whorton@msfc.nasa.gov)
Wed, 4 Oct 95 09:20:06 CDT

Maybe this is a simplistic observation, but I've never really taken the
notion of geocentrism seriously, so I've never really thought about its
possible validity. However, this issue bears directly on orbital
mechanics, which is based on the concept of a central force. When a
particle is within the sphere of influence of a massive body, the
gravity of that body affects the particle's motion. For decades now we
have been designing trajectories for interplanetary spacecraft using
orbital mechanics based on the observation that the sun is the dominant
body in the solar system. Clearly, the motion of objects in the solar
system (beyond close proximity to the earth) is primarily determined by
the influence of the sun (neglecting higher order effects from planetary
gravity). Doesn't that invalidate geocentrism?

Just lurkin',
Mark