The true temperature of thermal radiation of molybdenum and luminous flames is defined from the temperature dependences of generalized Wien's displacement and Stefan-Boltzmann's laws. For determining the true temperature of molybdenum, experimental values of either the position of the maximum of the spectral emitted density or the total emitted density are needed. It is shown that the thermal radiation of molybdenum belongs to the same universality class as that of tantalum, tungsten, and zirconium and titanium carbides. The thermodynamic functions of thermal radiation of molybdenum and luminous flames are constructed.