PAllen's latest activity

There is no requirement for constant proper acceleration. Constant position lines in FN coordinates based on a completely arbitrary...

A further nuance is that I think GR may allow a few cases that are not related to KVFs of the spacetime. Consider a stationary rigid...

Having thought about generalizing rigid motion theory from SR to GR, I believe we can all agree on the following for SC spacetime...

Ok, that is fine. However, what is true includes that, in an invariant sense, you can't place the rockets in the new locations at the...

Maybe not. I don’t see why you couldn’t arrange the threads to have no slack in the second case. The threads would just have different...

I will make a self correction which implies we were both right/wrong in a sense. Again, I think the correct analog to a well understood...

In my view, this is not a sensible approach. What you have is a collection of independent rockets, not a body. In a body, in any normal...

Another thought on this is to emphasize that spatial geometry is simply a choice of simultaneity, with the same conventionality as in...

I agree this is the fundamental question. I lean in the same direction as you (@pervect ). [This would mean that Herglotz-Noether...

What I know and don't know as of this point in the discussion: 1) You can have rigid body (congruence) of parametrized by varying r...

I think it is important to recall points made in some other threads about the limitations imposed by Herglotz-Noether : they apply to a...

But the real content of the theorem is what cases are possible. I have not been able to access discussions of this. The only things I...

The only such stresses on a rigid object, whatever its history, are those of tidal gravity.

Yes.

I am going to take some time responding to the rest of your post, but on this want to point out that the stationary congruence (constant...