The Planck mass, formed entirely from the fundamental constants of gravity and quantum theory, is widely believed to play an essential role in any future theory of quantum gravity(au81)
At high temperatures, distinction between the three forces, and between leptons and quarks, is completely lost. Matter enters a new and rather featureless phase. The temperatures concerned are enormous, about 10 to the 28 - 10 to the 30 K, at which the average thermal energy k T is not far short of the Planck mass-energy(au104)