How is the mass of the Galaxy estimated?
A) By observing the bending of light from distant galaxies as it passes near the Milky Way center
B) By observing its movement toward neighboring galaxies due to gravitational attraction
C) By counting stars and assuming an average stellar mass
D) By applying Newton's extension of Kepler's laws to the motion of the Sun and other stars

Question

Quizplus · Accepted Answer

The mass of the Galaxy is estimated by applying Newton's extension of Kepler's laws of planetary motion to the motion of the Sun and other stars. This involves measuring the orbital speed and distance of stars from the center of the Galaxy and using these to calculate the mass distribution of the Milky Way.

How Is the Mass of the Galaxy Estimated