Molecules have internal structure because they are composed of atoms that have different ways of moving within molecules. Kinetic energy stored in these
internal degrees of freedom contributes to a substance’s specific heat capacity and not to its temperature.
Hi Analog; Your naive thoughts are beyond this humble accounting professor. I always related heat or temperature to pressure, which I guess relates to degrees of freedom. It was my thought that the pressure was so great in that little tiny ball at the beginning of our universe, that it translated to temperature. Since the pressure was so great, so was the heat Just my thoughts on the matter. Best to you, Pat