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

Question

Quizplus · Accepted Answer

The mass of the portion of the Galaxy within the Sun's orbit can be calculated using the Sun's orbital velocity and its distance from the Galactic Center. This is because the orbital velocity provides information on the gravitational force acting on the Sun, and the distance allows for the application of Kepler's laws and Newton's law of gravitation to estimate the mass causing that gravitational force.

What Two Observations Allow Us to Calculate Mass of the Portion