[perhonen]

but... this is not true? McGaugh himself [1] mentions that there are mass discrepancies even using MOND analysis, and that this favors the dark matter paradigm [2].

[1] https://twitter.com/dudedarkmatter/status/109452639162072268... [2] https://twitter.com/DudeDarkmatter/status/109452792999493222...

certainly, these are still open questions in cosmology

[sahil50]

The tweets above are good questions! This is how to do science!

Meanwhile it's good to restate the obvious.

Modified gravity (MOND), where acceleration at galactic scales isn't just GM/R^2 but modeled as sqrt(GM/R^2 * cH/(2pi)), works for 100s of galaxies, and is more precise than cold dark matter (CDM).

Modified gravity only has one free parameter. cH/(2pi) = c^2 / 87 bly.

[8note]

Can the free parameter be described by something other than dark matter though? Or does it only put more constraints on what the dark matter is.

[sahil50]

Indeed. More detail here. https://news.ycombinator.com/item?id=29915004

Perhaps the "dark matter" of a galaxy is the rest of the galaxies of the universe.