PeterDonis's latest activity
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PeterDonis replied to the thread Graduate Jackson: justification of the Poynting vector by GR.But I didn't make use of that part of the article in my derivation in this thread. -
PeterDonis replied to the thread Graduate Jackson: justification of the Poynting vector by GR.Of course. Again, I think you misunderstood me. I was providing the link so that more of the equations that I was using would be seen...
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PeterDonis replied to the thread Graduate Jackson: justification of the Poynting vector by GR.The condition that the energy density of an electric field ##E## is ##E^2## (modulo some constant factors that depend on your choice of...
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PeterDonis replied to the thread Graduate Jackson: justification of the Poynting vector by GR.For some more background on why that's true, see my Insights article giving a short proof of the standard Birkhoff's Theorem...
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PeterDonis replied to the thread Graduate Jackson: justification of the Poynting vector by GR.They would also have to be compatible with the source-free Maxwell Equations. More precisely, since modifications to the SET mean...
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PeterDonis replied to the thread Graduate Jackson: justification of the Poynting vector by GR.Sorry, I misspoke. It's a specific form for the EM field tensor.
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PeterDonis replied to the thread Graduate Jackson: justification of the Poynting vector by GR.I'll take a stab at it here. I'll be making use of some equations from two of my Insights articles, on the EFE and Maxwell's Equations...
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PeterDonis replied to the thread Graduate Jackson: justification of the Poynting vector by GR.For reference, in MTW it's exercise 32.1.
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PeterDonis replied to the thread Graduate Jackson: justification of the Poynting vector by GR.Wald has it as part (c) of Problem 3 in Chapter 6. But note that the SET for this part is not "postulated". It is derived by first...
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PeterDonis replied to the thread Graduate Jackson: justification of the Poynting vector by GR.I'll see if I can find a reference to the theorem I mentioned.
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PeterDonis replied to the thread Graduate Jackson: justification of the Poynting vector by GR.I'm not sure it's just a matter of "postulating". The Reissner-Nordstrom metric, according to the theorem I referred to, is the unique...
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PeterDonis replied to the thread Graduate Jackson: justification of the Poynting vector by GR.Yes, and what Wald wrote is consistent with what you wrote in #2. Wald agrees that adding a term to the SET has gravitational effects...
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PeterDonis replied to the thread Undergrad Euclidean geometry and gravity.It depends on how the sheet is getting close to the BH. If it's freely falling, that's one thing. If it's being supported against the...
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PeterDonis replied to the thread Undergrad Euclidean geometry and gravity.I'm not sure what you're asking. What kind of scenario do you have in mind where an object might or might not break apart?
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PeterDonis replied to the thread Graduate Jackson: justification of the Poynting vector by GR.I'm not sure you are. The point of the passage from Wald that was quoted is not that there is a difference in the measurable effects of...