Evidence for dark matter is exhibited by the
A)relatively similar speeds at which all stars in a galaxy orbit the galactic nucleus.
B)speed at which galaxies orbit one another within clusters.
C)degree to which galaxy clusters exhibit gravitational lensing effects.
D)All of the above

Question

Quizplus · Accepted Answer

All three options are evidence for the presence of dark matter. The similar speeds of stars in a galaxy suggest the existence of additional matter beyond what we can see, which is known as dark matter. The speed at which galaxies orbit each other within clusters also implies the presence of additional matter, and the gravitational lensing effects seen in galaxy clusters can be explained by dark matter influencing the trajectory of light passing through the cluster.

Evidence for Dark Matter Is Exhibited by the