The sun is approximately 25,000 light years away from the centre of the milky way and moves around it, in an approximately circular path, in roughly 170 million years. let m be the mass of the galactic matter within a radius of 25,000 light years from the galactic centre. given that sunlight take approximately 8 min to reach the earth, what is the ratio of m to the mass of the sun? (a) 1.5x10 (b) 5x10 (d) 5x1012 (c) 1.5x1012