A rotation curve refers to a graphical representation that showcases how the speed of objects within a rotating system, such as a planet or a galaxy, changes as a function of their distance from the center. Full definition
«Because each dark matter halo should be unique, you should see lots of variation in rotation curves for the same galaxy,» he says. (scientificamerican.com)
«You don't expect the kind of uniformity that we observe in hundreds of galactic rotation curves.» (scientificamerican.com)
He set out to modify aspects of Newton's laws of motion so that they could naturally yield the flat rotation curves for galaxies. (discovermagazine.com)