2 ms·
> I've seen people create variants of MOND that try to address the Bullet Cluster problem, but you start having to have some sort of really weird gravity memory
by raattgift 10y ago
> I've seen people create variants of MOND that try to address the Bullet Cluster problem, but you start having to have some sort of really weird gravity memory effect in space or something, where space itself "remembers" that it used to have a lot of matter in it and still has a small amount of gravitation in it despite no longer containing the corresponding mass
Which variants are these?
cf. section 8.3, https://arxiv.org/abs/1112.3960 https://arxiv.org/abs/1112.3960
Several of the relativstic MOND theories (see chapter 7 of the same review) are detailed, and I don't see how any of the 8.3 set matches the quote above.
It's already a few years old, though, so maybe you've seen something newer.
> We also have a Standard Model of particle physics that, whatever its known flaws may be, doesn't immediately obviously have a hole for dark matter in it
There's a hole in chirality, which was part of the motivation for WIMPs as CDM.
There's a hole in the Strong-CP problem, which was part of the motivation for axions as CDM.
There's a hole in the hierarchy problem, also part of the motivation for WIMPs but also the motivation for Little-Higgs-like CDM.
Those particle dark matter candidates came from BTSM gauge theorists, not relativists.
> I also am sympathetic to MOND solutions as well.
If you make MOND relativistic you wind up adding a field to G = T; which side it's on doesn't really matter - it'd mostly be either down to an aesthetic choice based on coupling strength, or social considerations (this goes back to at least 1918! [1]).
[1] https://arxiv.org/abs/1211.6338 https://arxiv.org/abs/1211.6338 (and sure enough even in 2017 you will not be arrested by the EFE police if you put the cosmological constant onto the T side as a source, and you might even want to, e.g. in quintessence modelling, or in the cosmological frame; also cf. the choice between the Einstein frame and the Jordan frame for scalar-tensor gravity)