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

Question

Quizplus · Accepted Answer

A rotation curve is a graph showing how the orbital velocity of stars, gas, or other objects within a galaxy changes as a function of their distance from the center of the galaxy. It is commonly used to study the distribution of dark matter in galaxies, since the observed rotation curve often does not match what would be expected based on the visible matter in the galaxy. Choice B specifically describes a rotation curve for a spiral galaxy.

What Is a Rotation Curve