The Failure of Temperature Definition at Extreme Temperatures and the Physical Fictionality of Planck Temperature

Classical thermodynamics strictly defines temperature as a statistical average kinetic energy of irregular thermal motion of microscopic material particles, a definition that must rely on thermal collisions of solid particles and thermodynamic equilibrium systems. Nevertheless, fundamental logical contradictions persist in modern astrophysics and cosmology. While academia acknowledges that extreme high temperatures will completely disintegrate all microscopic material structures, it continuously adopts ultra-limit physical quantities such as Planck temperature and infinite singularity temperature of black holes, equating mathematically equivalent values to real thermodynamic temperatures. Relying on the unified theory of photon origin, this paper identifies 2 trillion degrees as the ultimate dissociation critical threshold for all material particles. Once the energy of a system exceeds this threshold, all atomic and subatomic particles fully dissolve, leaving only a pure photon energy aggregate with no volume or thermal motion within the system. As a result, the physical carrier of real thermodynamic temperature vanishes entirely, rendering the definition of temperature completely invalid. The extreme high temperatures of black holes and high-energy celestial bodies observed through astronomical detection are essentially equivalent radiation temperatures converted from the frequency spectra of escaping high-energy gamma photons. They merely serve as mathematical tools to quantify photon energy and do not represent genuine thermal motion inside the system. Planck temperature is a theoretical extrapolated value assembled purely through dimensional analysis, lacking any physical entity support or measured evidence. Moreover, its preconditions for existence collapse spontaneously in ultra-high temperature environments, making it a fully fictional physical concept. This paper thoroughly clarifies the essential boundary between real thermodynamic temperature and equivalent radiation temperature, resolves self-contradictions in black hole thermodynamics and extreme cosmic temperature systems, corrects long-standing conceptual confusion in modern physics, and achieves logical self-consistency between high-energy astrophysics and fundamental thermodynamics.