fast rotator so the area ratio can be estimated as . The other variables are constant. This calculation gives us an effective temperature of the Earth of . The literature gives a value of , which is essentially the 239 Wm-2 outgoing longwave radiation, one of two outgoing energy values of Earth's energy budget, the other being the reflected energy of 102 W⋅m−2. The average temperature of the Earth is . One reason for the difference between the two values is due to the greenhouse effect, which increases the average temperature of the Earth's surface. See also Brightness temperature Color temperature List of hottest stars References External links Effective temperature scale for solar type stars Surface Temperature of Planets Planet temperature calculator Stellar astronomy Planetary science Thermodynamic properties Electromagnetic radiation Concepts in astronomy