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rbj is offline
Jan22-06, 10:41 PM
P: 2,265
Quote Quote by Jeff Reid
Ok except for one minor detail. Use two beams coming in at different altitudes in the space ship. Since gravity changes with distance from the center of mass, if's it gravity affecting the beams,...
this accelerating space ship is out in the middle of nowhere and we're ignoring the graviational attraction of the space ship itself because its mass so much less than the mass of a planet.

... then one of them bends more than the other (may nead a really "tall" space ship to dectect this, but I'm talking hypothetical with infinitely accurate measurements). If it's acceleration, then both beams bend at the same rate.
yes, both beams bend the same amount.

I'm not so convinced about equivalency either. Light may bend [in the region of] a massive object simply because space is warped.
that's true . that is what GR says. in both cases the beam of light is in reality perfectly straight but appears to the observers be slightly bent because, in the spaceship case, the observer is in an accelerated frame of reference and in the earth's surface case, there is warping of spacetime because of the great mass the observer is in the vicinity of.

It's also possible that a strong gravtiational field attracts some form of dark matter or energy (stuff we can't detect) that simply refracts the light.
that's non sequitur, as far as i can tell.