Recent content by pervect

There's a paper that suggest an approach to explaining this problem using space-time diagrams. I like the approach a lot, but I haven't seen it actually work because - so far, at least - nobody on PF who has had an interest in the problem has gone so far as to do the work to draw said diagrams...

The numerical value of the energy of a photon (or for GR, a classical pulse of radiation because the quantum concept of photons is technically outside the classical scope of GR) is observer dependent as others have already noted. But there are a couple of points of interest that lead me to an...

I would say that the proper distance between the LIGO mirros changes with time when the gravitational wave passes. But, I'd say this is just one possible interpretation of the physics. Probably the biggest issue is how familair you might be with the concept of a metric. Are you familiar with...

The idea that a theory needs to be falsifiable can be traced back to the philosopher Karl Popper. This is about the philosophy of science - while I generally have a personal preference to avoid much of philosphy (which I can trace back to reading Feynamn's essay "Is Electricity Fire") this is...

I was thinking earlier that I should suggest you look at some of the already existing alternate formulations of special relativity. But hearing that your theory is somehow both the same and yet different than the standard formulation makes me wonder if that's going to work out. If the idea...

The language here is confusing. I wouldn't say that changing one coordinate result in changing another coordinate, given that changing a coordinate is defined by holding the other coordinates constant. If you have a 3 dimensional manifold with coordinates p,q, and r, ##\partial / \partial p##...

I know Kip Thorne liked the BKL singularity (this was mentioned in his popularization Black Holes and Timewarps), as does Andrew Hamilton (from https://arxiv.org/abs/1907.05292), but I hadn't heard about the numerical simulations. Is the BKL singularity generally accepted as being the likely...

I'm not sure why you think there is any effect other than spaghetification. I would have said that the reason people say that black holes destroy things is due to spaghetiffication, rather than anything more exotic. Onto hawking radiation. We don't have any direct experimental observation of...

Could you add a brief discussion of the units you use to the instructions/descriptions? Or which unit systems are compatible with it? I assume it's not SI because there are no annoying factors of c.

Assuming impossible things, in general, leads to contradictions. In fact, given inconsistent assumptions, it's fairly well known that one can prove anything one desires. The classic example is "Given that 2+2 =5, show that I am the King of England". I will append the details of the proof...

Not exactly. II do recall reading about acoustic models that have mathematical analogies to black holes that have been investigated experimentally, but I don't know the details. Google finds a theoretical paper by Matt Visser, https://arxiv.org/abs/gr-qc/9712010. Wiki mentions a paper by...

Reading your post (and Demystifers) did encourage me to consider a different case than the ones I had considered in the past, a case where we choose our freedom of how to distribute the stress that is needed to hold the disk together in such a way that it ends up not contributing to the energy...

I've come to realizie that when we spin up the disk, we have a choice to determine what stresses hold it together. If we make all the stresses radial, and make the circumferential stresses zero (or negligible), the problem becomes a lot more intuititve, and better behaved to boot. This was...

I recall a bit more about that now. The vector u is just the 4-velocity of a point on the rotating hoop. w is a vector perpendicular to u, representing the direction of the stress. Then ##\rho u \otimes u## is just a coordinate independent way of writing the stress-energy tensor contribution...

The system with rockets isn't a closed system, so I don't think it would be a good model at all. I'd question whether a non-closed system even had a definite invariant mass or energy, due to the relativity of simultaneity. I wouldn't have any objection to a system where the rockets exhcanged...