Re:Our universe within a larger universe? So suggests wormho...
by pdonis on Saturday February 23, 2013 @01:31AM
(#5268784)
I think we've exceeded the limits of HN discussion.
Probably, but I do see a couple of things in your post worth a brief comment:
You seem to be under the impression that the r coordinate is the space coordinate of the local inertial frame. It's not; it's a coordinate in a global coordinate chart. Two objects can be approaching each other with respect to the space coordinate of the LIF but be separating with respect to the r coordinate.
You also seem to be under the impression that the predicted trajectories in the LIF, if it could be extended indefinitely (which it can't), would have the particle inside the horizon moving outside it. That's not correct; the predicted trajectories in the LIF would have the particle outside the horizon falling inside it, then falling past the one that started out inside the horizon. (This has to be true because the horizon is moving outward at the speed of light, so neither particle can outrun it from the standpoint of the LIF.) The resolution of the puzzle does not depend on explaining why the particle that starts inside the horizon doesn't escape out; it depends on explaining why the particle that starts outside the horizon doesn't fall in even though the LIF predicts that it should.
Probably, but I do see a couple of things in your post worth a brief comment:
You seem to be under the impression that the r coordinate is the space coordinate of the local inertial frame. It's not; it's a coordinate in a global coordinate chart. Two objects can be approaching each other with respect to the space coordinate of the LIF but be separating with respect to the r coordinate.
You also seem to be under the impression that the predicted trajectories in the LIF, if it could be extended indefinitely (which it can't), would have the particle inside the horizon moving outside it. That's not correct; the predicted trajectories in the LIF would have the particle outside the horizon falling inside it, then falling past the one that started out inside the horizon. (This has to be true because the horizon is moving outward at the speed of light, so neither particle can outrun it from the standpoint of the LIF.) The resolution of the puzzle does not depend on explaining why the particle that starts inside the horizon doesn't escape out; it depends on explaining why the particle that starts outside the horizon doesn't fall in even though the LIF predicts that it should.