In the year 1054, a supernova explosion in went off in the Milky Way and was observed and recorded by ancient astronomers. The distance of the star that exploded is estimated to be 6500 light-years, and the supernova luminosity would have been approximately 10⁹ L_Sun (hint - only 1 sig fig here since the predictions for the luminosity of a supernova are uncertain) at its peak. Calculate the apparent brightness of supernova Betelgeuse in Watts/m2. Show all your work. Note that the Sun's luminosity 1 L_Sun = 3.8x10²⁶ W.