Re: Is my friend full of BS?

"srp" <srp2@xxxxxxxxxxxxxxxx> wrote in message news:44E6FBE2.5020508@xxxxxxxxxxxxxxxxxxx


Ok, but the point I was addressing was your comment that

"I made no mention of what was actually happening, whatever that means
anyway, _merely that you cannot tell the difference_. Your instruments
will not be able to tell either. You will measure 1g in both cases. "

My point was that contrary to a somehow general assumption, if you
are sitting in a thought-experimental spacecraft accelerating at 1g,
and if you use an thought-experimental instrument that measures the
relative acceleration of a falling internal component (referring to
your comment that "your instruments will not be able to tell either"),
you can tell the difference. The energy of the collision from a fall
for a given distance (any given distance) will in all cases be higher
in the craft than the same instrument measuring a fall for the same
distance at ground level.

You are imposing a "non-local" condition in order to try
to make your point, that is, that the divergence of the
gravitational field of the planet is measurably non-zero
for the distance of the fall.

The point of the equivalence principle is that you
cannot in any way distinguish the effects of a uniform
acceleration from a *uniform* gravitational field by
local measurements.
.

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