Question

Let us assume that our galaxy consists of 2.5 × 10¹¹ stars each of one solar mass. How long will a star at a distance of 50,000 ly from the galactic centre take to complete on revolution? Take the diameter of the Milky way to be 10⁵ly.

Answer 1

= 1.2 X 10¹⁶S  ⁼ \(\cfrac{1.12 \times 10^{16}}{86400 \times 365.25} years\) 

= 3.549 x 10⁸ years