In order to measure the speed of the Sun with respect to the center of the galaxy,it was necessary to establish a rest frame.What was used to establish this frame?

Question

Quizplus · Accepted Answer

The globular clusters in the halo were used to establish a rest frame because their velocities must average to zero, providing a good reference point for measuring the speed of the Sun with respect to the center of the galaxy. The other options do not provide a suitable reference point for establishing a rest frame.

In Order to Measure the Speed of the Sun with Respect