At 10:11 PM 7/5/98 -0700, John K Clark <email@example.com> wrote:
> >Damien Broderick <firstname.lastname@example.org>
> >Of course you can tell you're moving if you're in an accelerating
> >spaceship - the floor pushes on your feet.
>Special Relativity couldn't handle acceleration very well but according to
>General Relativity which Einstein developed about 10 years later there is no
>way to tell if you're in deep space accelerating at 1 g or at rest on the
>surface of the Earth experiencing the force of gravity.
This would only be so if the gravitation field of anything was uniform. Ergo, only if you measured gravity at one point on Earth might you think it was equivalent to a 1g acceleration in a spaceship. If you measured it at two points on the Earth's surface, you would notice, provided your instruments were very precise, that the direction of force converged. In a spaceship the force's direction at two separate points on the same surface (that was orthogonal to the direction of acceleration) would not converge. (This is all assuming space is locally flat.:)