The sun is approximated as a spherical black body with a surface temperature of 5762 K. The irradiation from the sun as measured by a pyranometer on earth's surface is 1353 W/m 2. The distance from the earth to the sun is approximately 1.5*10^11 m. Assuming that the sun radiates evenly in all directions, estimate the diameter of the sun. Ignore effects of reflection and refraction due to earth's atmosphere.