Sun is orbiting about the center of Milky Way at an average speed of v = 230 km/s, at a distance d = 26000 light years from the galactic center. Estimate the mass of the part of the Milky Way enclosed inside the solar orbit. To do that, you can assume that the solar orbit is circular and use the equation for orbital speed v = GM/d with M in the equation being the mass you are looking for. Recall that in this equation d must be in meters, and v in [m/s]. Express your result in the units of solar mass (e.g. as M = (number) ∗ MSun ).
