Vincent: Want to talk about MOND?
Jules: No man, I don’t consider MOND.
Vincent: Are you biased?
Jules: Nah, I ain’t biased, I just don’t dig MOND, that’s all.
Vincent: Why not?
Jules: MOND is an ugly theory. I don’t consider ugly theories.
Vincent: MOND makes predictions that come true. Fits galaxy data gooood.
Jules: Hey, MOND may fit every galaxy in the universe, but I’d never know ’cause I wouldn’t consider the ugly theory. MOND has no generally covariant extension. That’s an ugly theory. I ain’t considering nothin’ that ain’t got a proper cosmology.
Vincent: How about ΛCDM? ΛCDM has lots of small scale problems.
Jules: I don’t care about small scale problems.
Vincent: Yeah, but do you consider ΛCDM to be an ugly theory?
Jules: I wouldn’t go so far as to call ΛCDM ugly, but it’s definitely fine-tuned. But, ΛCDM’s got the CMB. The CMB goes a long way.
Vincent: Ah, so by that rationale, if a theory of modified dynamics fit the CMB, it would cease to be an ugly theory. Is that true?
Jules: Well, we’d have to be talkin’ about one charming eff’n theory of modified dynamics. I mean, it’d have to be ten times more charmin’ than MOND, you know what I’m sayin’?
Vincent: you mean, charming like … explaining the critical acceleration scale from first principles and stuff?
Jules: Sure. Now you can do that, you got my attention. What’s this thing they do across the pond, quantized inertia ?
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Could you enlight those of your readers who are not scientists about that paper : E.V. Karukes et al. The universal rotation curve of dwarf disk galaxies, Monthly Notices of the Royal Astronomical Society (2016). DOI: 10.1093/mnras/stw3055
Thanks for this blog,
John
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This paper says much the same thing as the radial acceleration relation: the rotation curve of a galaxy depends on its luminous mass and size. It is just phrased differently, and focuses on dwarf galaxies. When one specifies dwarfs, one gets a fairly typical characteristic rotation curve shape.
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Thanks again !
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