Quote:
Originally Posted by Ken G
It isn't necessary to prove one theory wrong to prefer another, all we have to do is pass judgement over which of the current possibilities makes the most useful predictions. I have never yet seen MOND make a significant prediction that worked, it is all retrofit. Dark matter makes predictions, and some have worked and others have not-- yet. So it is still pretty clearly the better of the two theories, which is the only question science asks. That doesn't mean it always will be.
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The part in bold is simply not correct.
Milgrom made predictions about galaxy dynamics that have been shown to be correct. See section VIII of the paper linked to. For example prediction #6 was shown to right on. Low Surface brightness galaxies show mass discrepancies of the form predicted by Milgrom. The mass discrepancy starts at a smaller radius than for High SB galaxies. Also as predicted by MOND, LSB galaxies follow the
same Tully-Fisher Relation as high SB galaxies.
McGaugh's papers provide an excellent read for the MOND issue. See
this paper and
this paper and
this paper .
In
section 4 of this paper it is shown that MOND cannot not be made to fit a hybrid galaxy that combines the rotation curve data for NGC 2403 with the photometry of UGC 128. MOND is unable to produce a fit to this hybrid galaxy (as would be expected since the galaxy is not real) whereas dark matter is able to make an acceptable fit to this galaxy. This is actually a problem for dark matter that it can be fit to a fictitious galaxy. There are too many free parameters to be fiddled with.
And then there are the
tidal dwarf galaxies that show mass discrepancies unexpected in the DM framework but are expected in MOND. And
Globular star clusters too.
Another paper on MOND and globular star clusters.