What surprising conclusion about the distribution of mass in our Galaxy has resulted from a study of orbital speeds across the galactic disk?
A) Most of the mass in the Galaxy is dark and is detected only by its gravitational influence.
B) Most of the mass of the Galaxy is in the form of hydrogen gas and giant molecular clouds in the outer region beyond the Sun's orbit.
C) Most of the Galaxy's mass is concentrated in a supermassive nucleus at the center of the Galaxy.
D) Most of the mass in the Galaxy is in the form of O and B stars.

Question

Quizplus · Accepted Answer

Studies of orbital speeds in the galactic disk have shown that there is not enough visible matter to account for the gravitational forces observed. This has led to the conclusion that most of the mass in the Galaxy is dark matter, which cannot be directly observed but is detected by its gravitational influence on visible matter.

What Surprising Conclusion About the Distribution of Mass in Our