Which Statement CORRECTLY Describes the Rotation of the Milky Way

question 443

Multiple Choice

Which statement CORRECTLY describes the rotation of the Milky Way Galaxy?

• A) The disk rotates like a solid object (objects at all distances take the same time to complete an orbit), and the halo objects have random orbits with no net rotation of the halo about the center of the Galaxy.
• B) Objects in the disk have random orbits with no net rotation of the disk about the center of the Galaxy, and the halo rotates differentially (objects farther from the center take longer to complete an orbit than objects closer to the center).
• C) The disk rotates differentially (objects farther from the center take longer to complete an orbit than objects closer to the center), and the halo rotates differentially (objects farther from the center take longer to complete an orbit than objects closer to the center).
• D) The disk rotates differentially (objects farther from the center take longer to complete an orbit than do objects closer to the center), and the halo objects have random orbits with no net rotation of the halo about the center of the Galaxy.