Yeah, tidal forces make a measurable difference between the guy on a planet and the accelerating elevator guy. Basically a planet is (more or less) spherical, so the gravity field isn't uniform over the flat floor of hte elevator, but pulls slightly towards the centre of the sphere. With sensitive enough instruments you could tell that two objects falling on either side of the elevator aren't moving along parallel courses, and hence tell the two cases apart.
The equivalence principle also assumes that gravitational and inertial mass are the same, which (although accurate to a very high degree) may turn out to not be exactly identical. (See the works of E.E. "Doc" Smith for what that would mean!) -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
