PAllen's latest activity

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...

So far as I know, Herglotz-Noether is purely a theorem of SR. The case described would definitely be a possible rigid motion in SR - you...

Thinking more about this, I come back to believing that for physics of materials, the only valid approach is in terms of kinematic...

I don't know that that is definitive. See my longer post on this, coming soon.

I am not quite sure how much of embedding theory corresponds to physics in pseudo-riemannian geometry, but I think it is worth pointing...

Claim: There is no difficulty defining a congruence of world lines representing a piece of paper far from a BH, that then has each...