As much as 90% of the matter in the universe may be unseen "dark matter." Where is this dark matter in galaxies?
A) Dark matter follows the same distribution as the stars inside galaxies.
B) Dark matter is concentrated in the centers of galaxies and may, in fact, be related to black holes at galactic centers.
C) Dark matter is concentrated in the planes of galaxies but extends far beyond the visible galactic plane.
D) Dark matter appears to be concentrated in spherical halos around galaxies that extend several times the radius of visible matter.

Question

Quizplus · Accepted Answer

Dark matter is theorized to exist in spherical halos around galaxies, extending well beyond the regions occupied by visible matter. This distribution helps explain the observed rotation curves of galaxies, which do not match the expected behavior if only visible matter were present.

As Much as 90% of the Matter in the Universe