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#91
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Galaxies without dark matter halos?
In article , greywolf42
writes: The original Hubble constant *is* a doppler shift. That modern cosmologists have converted this into an expansion parameter (that works just like a doppler shift, and has the same physics) is indeed splitting hairs. The physics of the universe is independent of who on Earth observed what when. Yes. What was your point? That you explain what you mean by "The original Hubble constant *is* a doppler shift.". |
#92
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Galaxies without dark matter halos?
In article , greywolf42
writes: At least the use of the Hubble constant is based on the assumption of known physics -- the doppler shift. As I've stated many times in this group, and a few times in this thread, providing references to referee-journal papers as well as less technical textbooks, the (bulk of the) redshift of objects at cosmological distances is not due to the Doppler shift. At large redshifts, this can get you into trouble. Even if you use the relativistic Doppler formula, you get the wrong answer. First, it is not clear WHICH of the many cosmological distances should have its temporal derivative correspond to the velocity in the formula. Second, the formula doesn't contain the cosmological parameters. If you believe the recession velocity at large redshift is given by the Doppler formula, then you must also believe that this velocity is independent of the cosmological parameters! |
#93
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Galaxies without dark matter halos?
In article , greywolf42
writes: At least the use of the Hubble constant is based on the assumption of known physics -- the doppler shift. As I've stated many times in this group, and a few times in this thread, providing references to referee-journal papers as well as less technical textbooks, the (bulk of the) redshift of objects at cosmological distances is not due to the Doppler shift. At large redshifts, this can get you into trouble. Even if you use the relativistic Doppler formula, you get the wrong answer. First, it is not clear WHICH of the many cosmological distances should have its temporal derivative correspond to the velocity in the formula. Second, the formula doesn't contain the cosmological parameters. If you believe the recession velocity at large redshift is given by the Doppler formula, then you must also believe that this velocity is independent of the cosmological parameters! |
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