Cosmology: Dark matter was initially proposed to explain
A) black holes.
B) stellar nebulae.
C) the expansion of the universe.
D) the velocities of stars and gases in spiral galaxy arms.

Question

Quizplus · Accepted Answer

Dark matter was initially proposed to explain the velocities of stars and gases in spiral galaxy arms, which could not be accounted for by visible matter alone.

Cosmology: Dark Matter Was Initially Proposed to Explain