[time-nuts] Pendulums & Atomic Clocks & Gravity

[Ulrich Bangert]

Arnold,

let us make one of the big experiments in physics and switch gravity
off. In the moment that we do so we see the satellite move away along a
straight line which is tangential to earth's surface. That is: Without
the presence of an force the satellite keeps its velocity AND its
direction as Newton's first law says. In a time delta-T it has moved
this tangential line a certain way which clearly depends on its
velocity. Note that it has ALSO moved an certain amount away from
earth's center. Now lets switch gravity on again. If "falling" due to
gravity during the time interval delta-T exactly compensates moving away
from earth due to the tangential movement you get... yes an circular
motion and yes of cource let delta-T go to zero to make it a smooth
motion. Only one force necessary: Gravity. If you are asking for the
gravitational force of the satellite on earth: Yes, it is there and in
reality the satellite does not exactly move around earth but earth and
satellite move around a common center of mass.