What two observations allow us to calculate the Galaxy's mass?
A)the Sun's mass and velocity in orbit of the Galactic Center
B)the Sun's age and period of the Galactic Year
C)the Sun's orbital velocity and its distance from the Galactic Center
D)the Sun's mass and its age
E)the Sun's composition and luminosity

Question

Quizplus · Accepted Answer

The two observations that allow us to calculate the Galaxy's mass are the Sun's orbital velocity and its distance from the Galactic Center. Through Kepler's laws, we can use these two observations to calculate the mass of the Galaxy, as well as the distribution of mass within it. By measuring the Sun's orbital velocity and its distance from the Galactic Center, we can use Kepler's laws of planetary motion and Newton's laws of gravity to calculate the mass of the Galaxy. This is because the gravitational force that keeps the Sun in orbit is proportional to the mass of the Galaxy, so we can solve for the mass using these observations. The other choices do not provide the necessary information to calculate the Galaxy's mass.

What Two Observations Allow Us to Calculate the Galaxy's Mass