Ludwig Boltzmann

Mathematical physicist responsible for many important developments in modern physics, but most notable for his invention of statistical mechanics. Boltzmann's work was important philosophically as well, as he was the first to remove determinism from physics, even before the development of quantum mechanics proper.

Ludwig Boltzmann was born in Vienna, Austria in 1844, and received a doctorate from that city's university in 1866. He went on to work at a large number of universities, never staying at the same place for more than a few years. A versatile scientist, his strong point was obviously theoretical physics, but he lectured on mathematics, experimental physics, and philosophy of science at various points in his career as well.

Unlike Henri Poincaré, who used strictly deterministic Newtonian mechanics to show that the so-called "eternal recurrence" made famous by philosopher Friedrich Nietzsche was possible in a closed system, Boltzmann worked with probabilistic mechanics on the microscopic scale. This new interpretation of atomic and molecular motion allowed him to derive the second law of thermodynamics. He believed Poincaré's derivation to be correct in theory, but sufficiently improbable to be unobservable.

Boltzmann was often at odds with his colleagues, and despaired when his efforts were attacked and rejected. While vacationing with his wife and daughter in 1906, he hanged himself. Soon afterward, his work was verified experimentally.

Some of the more important results attributed to Boltzmann:

• The Maxwell-Boltzmann distribution law, which describes the distribution of molecular speeds in an ideal gas.
• The Stefan-Boltzmann Law of the temperature dependence of blackbody radiation.
• Boltzmann's constant k.
• The famous relation between a system's entropy and number of possible states, S = k ln W, now known as the Boltzmann formula. This equation is inscribed on Boltzmann's tombstone in Vienna.