I’ve written a number of posts about the observational evidence behind dark matter. In yesterday’s io9, Alasdair Wilkins wrote a provocative story about an interesting paper by University of Maryland Astronomer Stacy McGaugh. The paper is a study of 47 gas rich galaxies, in which the rotation curves and gas masses are estimated. Stacy shows the relationship between rotational velocity and baryonic (ordinary) mass is exactly what a simple MOND calculation (without dark matter) would predict:
and, he argues, standard general relativity using dark matter, fits quite badly.
Alasdair cited my previous article, and I was delighted to get an email from Stacy this morning arguing the merits of MOND. He is quite persuasive, but ultimately I am not convinced.
If you’d like to see the complete debate, check this out.