How do astronomers most directly measure the amount of dark matter in elliptical galaxies?
A) through their rotation curves
B) through their velocity dispersion
C) through their radii
D) through their reddening

Question

Quizplus · Accepted Answer

Astronomers most directly measure the amount of dark matter in elliptical galaxies through their velocity dispersion, which is the measure of the range of velocities of stars within the galaxy. The velocity dispersion is affected by both the visible and dark matter components of the galaxy. By comparing the observed velocity dispersion with theoretical predictions, astronomers can estimate the amount of dark matter in the galaxy.

How Do Astronomers Most Directly Measure the Amount of Dark