Recent content by pervect

It looks more like you are trying to understand the relationship between two inertial frames of reference rather than the concept of a "proper reference frame". My graduate level textbook, Misner, Thorne, Wheeler "Gravitation", has a discussion of proper reference frames of possibly accelerated...

I'm not doubting your word on this, but a reference would be handy.I thought "extremal" and "stationary" were synonyms. For an I level example, f(x)=x^2 and f'(x)=x^3 are both extremal at x=0, because the derivatives df/dx and df'/dx both vanish. But the first is a minimum, the second is a...

It's always safer (though less understandable) to say that geodesics (of the Levi-Civita connection) are extremal rather than maximums or minimums. But for the Riemannian case, where one is not also dealing with time (and distances are always non-negative), it's a common simplification to say...

For a general way to get an intuitive feelings for geodesics that is not too advanced, I'll put in a plug for the "sector model" approach of Kraus and Zahn. There are a number of papers on sector models, the one that google finds specific to geodesics is https://arxiv.org/pdf/1804.09828...

A limited notion of parallel transport that works on a sphere is, IMO, a good place to start. One start with the notion that great circles are geodesics of the sphere. (If I'm being pendatic, which is sort of required to avoid having someone point out the oversimplification, I'll add that a...

Thanks - I can see why if the majority of the effect is due to "the missing inch" aka "space curvature", one might neglect Thomas precession in an introductory treatment, as it's apparently only half as large. I was trying (and failing) to recall what I had heard of the relative magnitudes...

Section 7 of the reference I quoted explains this in more detail: So yes I agree that Thomas precession is just one component of the total precession it's not sufficient in and of itself. We need to add to this the effect of parallel transporting a curve through the _spatial_ (emphasis...

I agree with your no answer to the OP's question, but you haven't mentioned Thomas precession at all. The best reference I have at the moment is https://arxiv.org/abs/0708.2490v1, "Gyroscopic precession in special and general relativity from basic principles". Unfortunately, it's not as...

As far as I know, this is just due to the ISS being deliberately locked to a constant orientation relative to the Earth, for practical reasons such as keeping the ground communications antenna's pointed at the ground station. So in one 90 minute orbit, the station rotates through 360 degrees.

Yes, I was in a bit of a rush - though I probably couldn't be that precise anymore anyways. (Was I ever? Probably not, not that it matters). But that's the essence of why I think the factor of 2 is not present in this case. Basically, a purely Newtonian calculation should be good enough to...

It would be bent twice as much by a mass. But I don't think not on an elevator. I don't have a reference for this statement, but I believe it to be true. If you want to be absolutely sure, you'll need to either do your own calculation of the path of light in a Rindler frame, look up such a...

There's a couple of different questions here. Basically, using devices that spin (such as the Forward Mass detector), can detect nearby massive bodies. The forward mass detector works by detecting tidal forces. There's a short reference to the forward mass detector in the wiki entry on...

Thank you. Untangling this in terms I can more fully understand will be quite a problem. I'm suspecting the issue is fundamental in that I'm viewing curvature as being defined by a metric. Which isn't necessarily how mathematicains view it. But I think the discussion has moved outside of...

Two dimensional

Not a paradox, but a rather hard problem. To deal with the problem with special relativity, I'd suggest replacing gravity due to mass due to the "artificial" gravity crated by an accelerated platform. The "paradox" then becomes the description of the accelerated platform with a different...