Question

The Milky Way has a diameter of about 150,000 light years. Our solar system is located 27,000
light years from the center of the Milky Way and orbits the center with a speed of 220 km/s.

(a) How long does it take for the solar system to circle the center of the Milky Way?

(b) The earth has formed about 4.5 billion years ago. How often has the earth circled the center?
​

Answer 1

Answer:

(a) 225-250 million years

(b) I didn't understand that question.