rotation curveFor a galaxy, a graph showing how the measured orbital velocity of stars and interstellar matter varies with distance from the center of the galaxy. A Keplerian rotation curve would indicate that most of the mass was concentrated toward the center. However, in many cases, the rotation curve is "flat"; in other words, the rotational velocity of the galaxy remains constant with increasing radius. This suggests that large amounts of dark matter exist beyond the visible region. Related category GALAXIESAlso on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History |