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 oen has the earth circled the center?​

Answer 1

Welcome Students,

◆ Answer -

(i) t = 2.31×10^8 years

(ii) N = 19.5 times

◆ Explaination -

# Given -

radius = 27000 light years = 2.55×10^17 km

(i) Time taken by our solar system to circle milky way -

Time = distance / velocity

t = 2πr / v

t = 2 × 3.142 × 2.55×10^17 / 220

t = 7.284 s

t = 2.31×10^8 years

(ii) No of times earth circled milky way -

No of revolutions = Total time / period of revolution

N = 4.5×10^9 / 2.31×108

N = 19.5 times

Hope this helped..