4 ms·

My guess would be something about the dynamics of dark matter in galaxy evolution pushes the distribution into a shape that produces those mathematically simple

My guess would be something about the dynamics of dark matter in galaxy evolution pushes the distribution into a shape that produces those mathematically simple rotation curves. That seems Occam's-razor compliant to me; it would be weird if rotation curves with dark matter were really complicated and unpredictable. It's also possible that both MOND and LCDM have some truth to them. But usually people are trying to get rid of dark matter, and that's just not happening.

naasking 4y ago
> My guess would be something about the dynamics of dark matter in galaxy evolution pushes the distribution into a shape that produces those mathematically simple rotation curves. That seems Occam's-razor compliant to me; It's not just rotation curves, there are numerous validated predictions MOND makes based only on the visible matter (see the paper at the bottom). These would all be a set of remarkable coincidences if the current CDM model were true. > it would be weird if rotation curves with dark matter were really complicated and unpredictable. It's also possible that both MOND and LCDM have some truth to them. Yes, this was the idea behind "superfluid dark matter", but it doesn't quite match observations either: https://arxiv.org/abs/2201.07282 https://arxiv.org/abs/2201.07282 Maybe another take on this fusion will stick. > But usually people are trying to get rid of dark matter, and that's just not happening. I'm not sure "usually" is an accurate summary. It's more like they're claiming that the standard CDM model is refuted or should be very disfavoured, which is not so unreasonable IMO: From Galactic Bars to the Hubble Tension: Weighing Up the Astrophysical Evidence for Milgromian Gravity, https://www.mdpi.com/2073-8994/14/7/1331/htm https://www.mdpi.com/2073-8994/14/7/1331/htm IIRC, some MOND proponents suggest that neutrinos can satisfy the dark matter observations that MOND itself doesn't explain. I believe that's discussed in the above paper but it's been awhile since I've read it.
- andrewflnr 4y ago
  The bulk of the whining I see here about DM is on the lines of "but it's not directly observable, so it can't be real science! Can't you see this is just Big Physics trying to fool you?" These are the ones trying to falsify DM entirely, and having to ignore huge swathes of evidence to do so. Yes, the paper suggests sterile neutrinos at cluster scale, with MOND at galaxy scale. I'm fine with this, honestly.

naasking 4y ago

> My guess would be something about the dynamics of dark matter in galaxy evolution pushes the distribution into a shape that produces those mathematically simple rotation curves. That seems Occam's-razor compliant to me; It's not just rotation curves, there are numerous validated predictions MOND makes based only on the visible matter (see the paper at the bottom). These would all be a set of remarkable coincidences if the current CDM model were true. > it would be weird if rotation curves with dark matter were really complicated and unpredictable. It's also possible that both MOND and LCDM have some truth to them. Yes, this was the idea behind "superfluid dark matter", but it doesn't quite match observations either: https://arxiv.org/abs/2201.07282 https://arxiv.org/abs/2201.07282 Maybe another take on this fusion will stick. > But usually people are trying to get rid of dark matter, and that's just not happening. I'm not sure "usually" is an accurate summary. It's more like they're claiming that the standard CDM model is refuted or should be very disfavoured, which is not so unreasonable IMO: From Galactic Bars to the Hubble Tension: Weighing Up the Astrophysical Evidence for Milgromian Gravity, https://www.mdpi.com/2073-8994/14/7/1331/htm https://www.mdpi.com/2073-8994/14/7/1331/htm IIRC, some MOND proponents suggest that neutrinos can satisfy the dark matter observations that MOND itself doesn't explain. I believe that's discussed in the above paper but it's been awhile since I've read it.

andrewflnr 4y ago
The bulk of the whining I see here about DM is on the lines of "but it's not directly observable, so it can't be real science! Can't you see this is just Big Physics trying to fool you?" These are the ones trying to falsify DM entirely, and having to ignore huge swathes of evidence to do so. Yes, the paper suggests sterile neutrinos at cluster scale, with MOND at galaxy scale. I'm fine with this, honestly.