Bernie, The rate of decay of an inverse-square relationship is most definitely not linear and hence a linear extrapolation is totally meaningless. Neville. Bernard Brauer <bbrauer777@xxxxxxxxx> wrote: ... Gravity decreases with height, at a rate which near the surface of the Earth is such that linear extrapolation would give zero gravity at a height of one half the radius of the Earth, i.e. ... --------------------------------- Inbox full of unwanted email? Get leading protection and 1GB storage with All New Yahoo! Mail.