PeterDonis's latest activity

Of course not. We're not disputing that treating the object as a test object as far as determining the spacetime geometry is concerned...

We're not talking about having the object affect the spacetime geometry; we're assuming the spacetime geometry is fixed. We're talking...

I'm wondering why you said this:

Are you claiming that this statement is true?

A spacelike geodesic in the Flamm paraboloid. Note that such a curve is not one that either an ordinary object or a light ray will...

Zero or negligible, it's still pointless. You're making it negligible by making the beam itself negligible. Which means we can just...

If you build the object in curved spacetime, hovering against gravity, you can't make the stresses in it negligible, because it's under...

Meaning, you build the object in an accelerating spaceship or something like it in flat spacetime, and then bring it into curved...

A beam of "negligible mass" might as well not be there; you're only getting the result that the stress in it is zero by saying it has no...

The OP specified a piece of paper, not a truss structure. Also, your claims, if they are correct, should apply to any object, not just...

Really? You can externally apply a force to an atom in the center of the object? You can't apply an external force to a part of an...

Btw, for the particular special case under discussion in this thread, we don't even need the Riemann tensor, because we know that the...

I strongly suggest that you do the math. If you do, you will find that your statement here is false. First, the "spatial curvature" you...

Yes, that's true, but... Yes, which is why the stationary congruence does not fall into the first type of congruence that the H-N...

While the theorem was originally proved before GR was even discovered, AFAIK it does not actually require flat spacetime. The two types...