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Astronomy and Cosmology
Astronomy and Astrophysics
Red-Shifting vs. Luminosity Question
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[QUOTE="Ibix, post: 6516520, member: 365269"] It doesn't say that. In fact it says almost the opposite. The equivalence principle says that free falling in the absence of gravity is indistinguishable from free falling in a gravitational field using local measurements. That means that if we are in a closed box and experience acceleration we also cannot tell if we are accelerating in free space or are at rest on the surface of a planet (or star). The angular diameter of the star is affected by its gravitational field (gravitational lensing, essentially), so I suspect that there are probably some subtleties around angular aberration, similar to the point Bandersnatch is making. By neglecting them, I think that you are implicitly integrating flux over a sphere enclosing the star. Since this is most definitely not a "closed box" local measurement, it wouldn't particularly surprise me if we could see effects of the gravitational field. (Obviously we could have a black body in our closed box and move around it, but sometimes we'd be below it and sometimes above - not so with the star which would always be below us.) [/QUOTE]
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Red-Shifting vs. Luminosity Question
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