Recent content by Povel

@PAllen I think there might be some confusion about what I'm arguing. Let me clarify by summarising all the points I've raised throughout this discussion. My original concern with Raine's text centers on a basic tensor invariance issue. When I reproduced his calculation using proper Rindler...

I found a paper that analyses explicitly the EFE to post-Newtonian order for a frame of reference having an arbitrary time-dependent translational acceleration and an arbitrary time-dependent angular velocity by Nelson https://link.springer.com/article/10.1007/BF00756150 The resulting equation...

@PAllen No this is not about Nordtvedt effect. I posted the article link in post 3, here is the link again https://link.springer.com/article/10.1007/BF00671317 I didn't know the article you attached though. thank you Sorry, what I meant was that the effect mentioned by Nordtvedt has...

I understand why Raine's article isn't correct. However, either I don't understand or I misunderstood some subtleties about Norvedt's article. Quoting from the article right before and after equation 14: It appears that the accelerations involved here are gravitational in the Newtonian sense...

Thank you. Out of curiosity, I attempted to perform the calculation in Rindler coordinates. It boils down to calculating the antisymmetric derivative of the stress-energy tensor. In these coordinates, the Christoffels are not zero, and unsurprisingly, the derivative is zero in the end. It...

I've been reading Derek Raine's paper "Integral formulation of Mach's Principle" from the book "Mach's Principle" by Barbour, and I've hit something that's really bothering me. It seems like there's a problem in how he treats coordinate transformations and the Weyl tensor. Here are the relevant...

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...