"James R. Freeman" wrote in message ...
He is right. Gravity is not constant from one location to the next. For
example if we look a W. 105 and move to W. 15 we have moved from a gravity
hole to a gravity peak.The core of the Earth is like spinning a egg, in our
case the core has not come up to the speed of the surface and locations of
higher mass move but give us the 2 valley 2 peak problem in mass/gravity. It
is very much to note if You are doing station keeping on a geo-syn sat. .

You can also stay at the same location and exoperience varions
in the _apparent acceleration_ do teo gravity. I wouldn't call that
Gravity not being constant. For Gravity to be inconstant would
require that the Gravitational constant vary.

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FF