Solar System Energy
Updated 20190918
Planetary energy balance:
Blackbody Emission
AKA blackbody radiation.
There are two conditions required for blackbody radiation:

The body must be in thermal equilibrium  has a welldefined temperature T

The body is dense/opaque such that photos can’t simply pass through it but instead bounce around many times on the way to exiting.
The total flux of blackbody radiation is given by: \(F=\sigma T^4\quad[\text{Js}^{1}\text{m}^{2}]\) Where $\sigma$ is the StefanBoltzmann constant which is 5.56×10^{8} Js^{1}m^{2}K^{4}.
For humans, our body is at 310 K, objects radiate about 500Wm^{2} where 1W is 1Js^{1}. If the average human surface area is 2m^{2} then we radiate about 1000W.
The surface of the Sun is around 5780K. Which radiates about 6.3×10^{6} Wm^{2}.
Now we looked at the total flux, it’s actually an integral of the intensity for all wavelengths: \(F=\sigma T^4 = \pi\int_0^\infty I_\lambda \mathrm d\lambda\) Where $I_\lambda$ is the intensity per unit wavelength.
Temperature is the only parameter needed to describe the blackbody radiation.