. By looking at distant galaxies, astronomers have concluded that our solar system is circling the centre of our galaxy. The hub of our galaxy is about 2.7 x1020 m from our Sun and our Sun circles the centre every 200 million years. We assume that our Sun is attracted by a large number of stars at the hub of our galaxy and that the Sun is kept in orbit by the gravitational attraction of these stars: a. What mass is at the centre of our galaxy? . How many Sun size stars is this equal to