Dust in galaxies does not count as dark matter because
A) it absorbs only some wavelengths of light but not all wavelengths as dark matter does.
B) it interacts with light.
C) it is found only in spiral disks, whereas dark matter is also found in elliptical galaxies.
D) dust is easily destroyed by dark matter.
E) there is never enough to account for all the gravity in galaxies.

Question

Quizplus · Accepted Answer

Dust interacts with light by absorbing and scattering it, whereas dark matter does not interact with light in this way.

Dust in Galaxies Does Not Count as Dark Matter Because