A derivation of a theoretical , time average , cosmic microwave background ( CMB ) , Planckian temperature V of the universe remains a challenge .
A scalar potential model ( SPM ) that resulted from considerations of galaxy cells is applied to deriving a value for V .
The heat equation is solved for a cell with the boundary conditions of SPM Source and Sink characteristics , with simplified cell characteristics , and with zero initial temperature .
The universe is a collection of cells .
The CMB radiation is black body radiation with the cells acting as radiators and absorbers .
Conventional thermodynamics is applied to calculate V = 2.718 …K .
The temperature and matter content of cells are finely controlled by a feedback mechanism .
Because time is required for matter to flow from Sources to Sinks , the radiation temperature of cells cycles about V after an initial growth phase .
If the universe is like an ideal gas in free expansion and is not in thermal equilibrium , then the pressure and volume follow the measured CMB temperature v _ { \mathrm { m } } = 2.725 \pm 0.002 K. Therefore , increasing v _ { \mathrm { m } } > V equates to an expansion pressure on matter and expanding volume .