Was just watching an "intro" lecture[1] on DM over at PIRSA, as part of TRISEP 2023[2], a summer school for grad students. There he goes over some of the arguments for DM, but with more math and details than the usual popsci stuff, but still at a fairly accessible level.
I'm just a layman but to me the Bullet Cluster[3] seems very hard to reconcile with just modified theories of gravity. On the other hand it seems unreasonable to me that General Relativity doesn't need corrections due to quantum mechanics, and as this article mentions LCDM has a bunch of other issues.
So how about both? Some non-interacting "dark" particle(s) and some quantum corrections to General Relativity. Anyone know about work trying to combine the two approaches, and see how things stack up?
It's a bit of a false dichotomy. Even the MOND people recognize that you need dark matter (even if they don't use the term) to explain the bullet cluster, so it isn't really dark matter vs MOND.
LCDM also apparently fails to explain the velocity of the bullet cluster, so it's not like it's slam dunk for DM (collision velocity better matches MOND).
Some MOND proponents posit "sterile neutrinos" to complete the theory in some cases, like the bullet cluster. And then there are bullet cluster-like failures for LCDM that get papered over:
There have also been recent measures that suggest that much existing data is actually more consistent with warm regular matter that has so far gone undetected rather than cold dark matter.
The dark matter "consensus" is a flimsy facade covering a lot of gaping holes. Something's gotta give.
With JWST it seems we might be able to get closer to an answer[1]. Sterile neutrinos[2] seemed like an obvious candidate, but we'll see how that pans out. Current searches aren't positive[3][4], but I suppose it's far to early to call it quits on that given the theoretical motivation.
I'm just a layman but to me the Bullet Cluster[3] seems very hard to reconcile with just modified theories of gravity. On the other hand it seems unreasonable to me that General Relativity doesn't need corrections due to quantum mechanics, and as this article mentions LCDM has a bunch of other issues.
So how about both? Some non-interacting "dark" particle(s) and some quantum corrections to General Relativity. Anyone know about work trying to combine the two approaches, and see how things stack up?
[1]: https://pirsa.org/23060067
[2]: https://pirsa.org/C23020
[3]: https://en.wikipedia.org/wiki/Bullet_Cluster