Let us consider that our galaxy consists of `2.5xx10^(11)` stars each of one solar mass. How long will this star at a distance of `50,000` light year from the galastic entre take to complete one revolution? Take the diameter of the Milky way to be `10^5ly. G=6.67xx 10^(-11) Nm^(2) Kg^(-2). (1 ly= 9.46xx10^(15)m)`