Ludwig Boltzmann, Austrian physicist and philosopher (born 1844)

Ludwig Eduard Boltzmann was an Austrian mathematician and theoretical physicist. His greatest achievements were the development of statistical mechanics and the statistical explanation of the second law of thermodynamics. In 1877 he provided the current definition of entropy, , where Ω is the number of microstates whose energy equals the system's energy, interpreted as a measure of the statistical disorder of a system. Max Planck named the constant k_B the Boltzmann constant.