earth
posted by Samantha .
The globalmean surface temperature of the earth is about 288 degrees Kelvin. Use the StefanBoltzman law to calculate the radiative flux corresponding to an object with this temperature. [hint: use σT4 with σ = 5.67x108 Wm2K4 ]

what's the problem? You have the formula:
5.67x10^8 * 288^4 = 390.08W/m^2