Heaven, apparently…
Not many people know about the branch of Christian apologetics known as Theological Thermodynamics. Here is a good summary of the state of current knowledge in this vital field. That webpage discusses some of the most important breakthroughs that have been made.
For example, in a 1972 article in Applied Optics, it was shown that Heaven is, somewhat counter-intuitively, hotter than Hell. This was done using biblical evidence and scientific formulas. Isaiah 30:26 and the Stefan-Boltzmann fourth power law for radiation show that Heaven will be a balmy 525°C (equal to 977°F). On the other hand, although there is not enough biblical evidence to pin down the exact temperature of Hell, it must be less than 444.6°C (equal to 832°F), since this is the temperature at which sulfur and brimstone turn into a gas – and, despite what some liberals might say, you can’t have a gaseous Lake of Fire.
In a follow up article, one Dr. Tim Healey, F.R.C.R.; M.I.Nuc.E., who thought that the calculation of Heaven’s temperature “is hard to find fault with”, argued that the original calculation of the temperature of Hell may have missed a crucial point by not taking the pressure into account. You see, the enormous number of damned souls (which he estimated to be at least 29,422,641,251,519,917,000, or approximately 4.2 billion times the current population of the earth) crammed into the valley of Gehinnom (with an area of at most 7,000,000 square meters) would have the effect of significantly raising the atmospheric pressure, to the point that Hell would, thankfully, be quite a lot hotter than Heaven. Phew! Even though Heaven will still be “deucedly hot”…
And it’s totally legit. Trust me… I’m a mathematician!