One piece of evidence for the existence of dark matter is the
A) absence of interstellar materials (gas and dust) from elliptical galaxies.
B) low count of neutrinos emitted from the center of the Sun.
C) scarcity of dwarf ellipticals in the Local Group of galaxies.
D) discrepancy between observed mass and the required gravitational binding in rich clusters of galaxies.

Question

Quizplus · Accepted Answer

The discrepancy between the observed mass (calculated from visible matter) and the mass required for gravitational binding in rich clusters of galaxies is a key piece of evidence for the existence of dark matter. This unseen mass is thought to account for the additional gravitational force needed to hold these clusters together.

One Piece of Evidence for the Existence of Dark Matter