Recent content by exmarine

I also have all his books I could find.

Webb telescope. I don't think prisms have anything to do with GRT. Thanks for the link.

I reviewed the derivation / solution of that GRT problem and do not see any dependence on the wavelength of the light. Is that correct, or am I missing something? This makes me wonder about my understanding of how prisms work. How or why do longer wavelengths go slower in glass than shorter...

First, in section 20.4, after listing all the things gravitational potential energy does not do, they say the equivalence principle forbids it being localized. I thought I understood the equivalence principle, but maybe I don’t. Any comments explaining that would be appreciated. Second, they...

Thanks for the responses! But no I do not have access to a technical library. The nearest one (UVA) is about 100 miles away, I am retired and have to take care of an ailing spouse. So I do not even know what journals are out there, much less have any familiarity with their contents, styles, etc...

Summary:: I would like to write a paper about a subject germane to this forum,... I would like to write a paper about a subject germane to this forum, i.e., general relativity, frame dragging, dark matter, etc. I have no connection to any academics, so I don’t know and can’t ask anyone what...

The Schwarzschild metric seems to model, for example, the earth’s gravity field above the earth’s surface pretty well, even though the Earth is not really a golf-ball sized black hole down at the center. Can the same be said for the Kerr metric? Does it model a rotating extended body’s gravity...

Do gravitational lensing observations support the need for huge amounts of DM? If so, what do the MOND proponents say about that?

Since it is nonlinear, the 3 leg lengths would be limited to differentials? But how would the metric coefficients be incorporated into those leg lengths? It seems like the leg differential lengths would have to vary inversely with the magnitudes of the metric coefficients? For example, near...

Ah thanks FRODO. That is basically what I am doing. I have a PDF printer installed, and regularly use FireFox as well as Edge. But that has always produced jumbled and garbled page headers and text, basically unreadable. RUTA kindly made his Word file available, but it had the equations and...

Yes please. And thanks!

Is there some way to download threads like this, say to a pdf, so I can study them off-line? When I hit print in the Edge browser, I do not get a very good printout. Thanks.

Thanks for the responses. My question was not about the tidal effects on a physical clock. It was about how a physical clock could occupy the spatial locations for both events as space expands. And how do you get from this equation (which I think is the definition of proper time?) (and I can't...

If a proper time measuring clock goes along for the ride between events, then is such a clock physically possible as the scale factor changes / increases in the Friedman metric? How could any clock have zero spatial changes for that situation?

I should paste links to Brown’s online book in case anyone else is interested. https://www.mathpages.com/rr/s6-02/6-02.htm I see that he has revised this section. He removed the sentence I quoted and added an appendix discussing this very issue. (He also renumbered his equations, so it might...