There is a large visible mass between the external pelvic bone and the muscle. (wagwalking.com)
The measured rotation speeds on the outskirts of a spiral galaxy, Milgrom says, depend in «a very strict manner only on the total visible mass of the galaxy.» (scientificamerican.com)
«In 1933 the late Fritz Zwicky pointed out that the galaxies of the Coma cluster are moving too fast: there is not enough visible mass in the galaxies to bind the cluster together by gravity. (creationscience.com)