Recent content by Povel

I also thought about Rindler coordinates, though I'm not capable to calculate what the charge distribution on the inertial shell would look like. I posted the paper reference and the passage in my previous post. Could you please elaborate on this? Why this invariant being zero means that...

Sorry I didn't post it here to not overload my initial post. Here is one of the papers in question The relevant passage is at page 1720 (26 in the pdf). Quoting from it: Concerning my assumptions, I'm not sure how to disentagle them up, but I hope that by reading the above quoted passage...

I did not stipulate any special property to the test charge mentioned in the question, so in an actual setup it might be represented by any sort of charged macroscopic object / electric field detector, as long as its presence doesn't alter the system in a significant way. Its acceleration could...

Sorry for the silence, this week I didn't have and still don't have any moment to reply properly. I should be able to do so and clarify my question better over the next days, hopefully. Thanks in advance for all your replies 🙂

The electric field inside a charged spherical shell moving inertially is, per Gauss's law, zero. If the spherical shell is accelerated, the field inside is not zero anymore, but it gains a non-null component along the direction of the acceleration, as mentioned, for example, in this paper. The...

At least in the case of Newtonian gravity, such a region with homogeneous acceleration can be found inside a non-concentric spherical cave in a spherical body with uniform density. There are no tidal forces inside the cave. I don't know if the same is also true in GR (the demonstration involves...

Sorry for the ignorance, but a pole is also "on a line", but it has a non-null quadrupole moment that changes if the length of the pole changes, no? What is the difference between it and the mass-energy distribution of the (perfectly collimated) photon rocket + emitted photons?

I guess that naively one would expect the quadrupole moment to change. Afterall the total system of photon flux + mass accelerating due to recoil is changing shape. That the system nonetheless does not emit gravitational waves has surprised some people, at least Bonnor and Damour. The...

Thank you for the reply Peter. Your explanation makes a lot of sense, but there are still a number of things that are unclear to me concerning the difference between a "radiative term" in the connection/gravitational field and gravitational waves/radiation:-As you point out, for having a change...

I am going to add some further elements. Hope it will help anyone kind enough to try answering my question. Of course, for getting the full picture is better to read the paper(s). In Carlip's paper he obtains from the Lienard-Wiechert potential the following expression for the electric field...

In this paper by Carlip, a comparison is made between electromagnetic and gravitational aberration. For the latter case, he takes as a study subject the Kinnersley’s “photon rocket”, an exact solution which is known to have the strange property of not producing any gravitational waves, even...

Ok, I see how this works for static situations, but the discussions over Mach's principle usually deal also with acceleration, both proper and coordinate, of either the local observer mass or the distant universe/"cosmic shell". I don't see how it is possible to evade the need of employing some...

Of course, but what I meant was specifically how an interaction involving the geometry of spacetime could "travel" to us aside from propagating through gravitational waves. I know Wheeler and Ciufolini talk about "instantaneous" elliptical constraints equation applied on a space-like...

So there are ways, different from gravitational radiation, in which the influence of some distant mass can propagate to us in a causality-respecting way? For example? Very interesting, I didn't know about this solution, thank you for mentioning it. So, if I'm intepreting it correctly, it...

Thanks for your quick answer PeterDonis :) I expressed myself incorrectly. With "relative" I meant exactly the content of your last sentence, that is objects feel proper acceleration due to the effect of the distribution of mass and energy in the universe. I agree fully, there must be a time...