How do we know the total mass of the Milky Way Galaxy that is contained within the Sun's orbital path?
A)by applying Newton's version of Kepler's third law (or the equivalent orbital velocity law)to the Sun's orbit around the center of the Galaxy
B)by counting the number of stars visible in this region of the galaxy
C)by using the law of conservation of angular momentum to calculate the orbital speeds of nearby stars
D)by estimating the amount of gas and dust in between the stars

Question

Quizplus · Accepted Answer

By applying Newton's version of Kepler's third law (or the equivalent orbital velocity law) to the Sun's orbit around the center of the Galaxy, we can calculate the total mass of the Milky Way Galaxy contained within the Sun's orbital path. This is because the mass of the galaxy affects the orbit of the Sun around the center of the galaxy, and we can use this information to calculate the total mass. Counting the number of stars visible, using the law of conservation of angular momentum, or estimating the amount of gas and dust in between the stars would not provide an accurate measure of the total mass.

How Do We Know the Total Mass of the Milky