Someone just proved the laws of physics wrong

Well, they’re always wrong, or subject to revision, but this is pretty interesting. Familiar with Dark Matter, the matter which we can’t detect but have to assume exists to make all our sums right? Well perhaps our sums were just plain wrong:

A modified law of gravity correctly predicted, in advance of the observations, the velocity dispersion—the average speed of stars within a galaxy relative to each other—in 10 dwarf satellite galaxies of the Milky Way’s giant neighbor Andromeda.

The relatively large velocity dispersions observed in these types of dwarf galaxies is usually attributed to dark matter. Yet predictions made using the alternative hypothesis Modified Newtonian Dynamics (MOND) succeeded in anticipating the observations.


At stake now is whether the universe is predominantly made of an invisible substance that persistently eludes detection in the laboratory, or whether we are obliged to modify one of our most fundamental theories, the law of gravity,” McGaugh continued.

The MOND hypothesis says that Newton’s force law must be tweaked at low acceleration—11 orders of magnitude lower than what we feel on the surface of the Earth. Acceleration above that threshold is linearly proportional to the force of gravity—as Newton’s law says—but below the threshold, no. At these tiny accelerations, the modified force law resolves the mass discrepancy…

via Noahpinion. More at the above link.


3 thoughts on “Someone just proved the laws of physics wrong

  1. Oh, good lord, MOND… Yes, it explains galactic rotation curves very well – even better than DM does. Unfortunately, it completely and utterly fails to explain any of the many other things we need DM to explain. Even the strongest proponents of MOND now acknowledge that we still need DM. Ethan Siegel has a number of very good posts over on SciBlogs on the topic. Start here and then use the tags if you want more – he has a series called “Messier Monday” which unfortunately makes a simple search for “MOND” useless…

    In the world of physics, DM really isn’t that far out. It may sound it to the layman, but we know for a fact that there’s loads of particles out there which are incredibly difficult to detect. Postulating an additional one that happens to be massive is no great stretch. MOND, on the other hand, really is pretty far out, and solely invented as a mathematically tweak to make one particular set of sums work, with no theoretically plausible physical basis so far as I’m aware. (Which I have to admit isn’t very far.)

    1. This is why I like having you around so much Dunc! Thank you.

      I’ll follow the links later.

      Haven’t got anything clever to add. Dark matter and energy just sound really ugly to me. I don’t like them. But I guess the universe doesn’t have to be aesthetically pleasing to me.

      1. Yeah, I’ve never really understood why people don’t like dark matter or dark energy… I’d have thought that once you’ve accepted the basics of relativity and quantum mechanics, you should have realised that the Universe is a deeply weird place that doesn’t have any obligation to make sense to mere humans. (Which I suspect may be part of the attraction of MOND – the N stands for Newtonian after all…)

        But then I suspect that most people only pretend to grasp relativity and QM, based on the ludicrous over-simplifications of popular science programmes. Not that I can really claim to grasp it any better, but I do at least have enough physics to know how little I know, and how over-simplified those programmes are.

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