What is a rotation curve?
A. a precise description of the shape of a star's orbit around the center of the Milky Way Galaxy
B. a graph showing how orbital velocity depends on distance from the center for a spiral galaxy
C. a curve used to decide whether a star's orbit places it in the disk or the halo of a spiral galaxy
D. a graph that shows a galaxy's mass on the vertical axis and size on the horizontal axis
Answer:B
What is a rotation curve?
A. a precise description of the shape of a star's orbit around the center of the Milky Way Galaxy B. a graph showing how orbital velocity depends on distance from the center for a spiral galaxy C. a curve used to decide whether a star's orbit places it in the disk or the halo of a spiral galaxy D. a graph that shows a galaxy's mass on the vertical axis and size on the horizontal axis