This van der Waals fluid relationship to heat flow turned out to be really interesting.
The reduced form of the equation of state for any fluid is:
Adding the stefan-boltzmann constant with T^4 on the right side and T^4=TSI:
Apparently, light can, and maybe should, be treated like a form of fluid. This of course gives me some interesting ideas about space and what fills the vacuum, and how massive bodies are affected by it.