The main source of heat on Earth comes from solar energy that is transmitted from the Sun to Earth through radiation and is converted to heat at Earth's surface. To balance this input of solar radiation, Earth must emit radiation back to space. Therefore, Earth must be in energetic equilibrium between the radiation it receives from the Sun and the radiation it emits out to space. From this equilibrium we can calculate the effective temperature (T _E ) of Earth::

Where Fs is the solar radiation flux from the sun that is intercepted by the Earth (1370 W/m ² ). A is the planetary albedo and represents the fraction of incoming radiation that is reflected back to space by clouds, snow, ice-i.e, anything that is light coloured and reflects radiation (currently Earth has an albedo of 0.28), and σ is the Stefan-Boltzmann constant (5.67 x 10-8 W/m2K4).

Using the equation and values given above, calculate the effective temperature (TE) of Earth.

1. O256.8043 K or-16.3457 C
2. O 256.8043 C or 529.9543K
3. O -16.3457 F or 246.29127 K
4. O0.0257 Kor -273.1243 C
5. O 0.0257 For-17.7635 F