Ludwig Eduard Boltzmann

1844-1906

Austrian Physicist

Ludwig Boltzmann was an important figure in the development of physics as the science made the transition from the classical physics of Isaac Newton (1642-1727) to the physics of the twentieth century. His work helped to usher in the fields of statistical mechanics (used to describe the behavior of fluids) and helped to better explain the Second Law of Thermodynamics. He became embroiled in controversy as European scientists debated the validity of his work, eventually winning recognition and acceptance shortly after his death.

Boltzmann was born in Vienna, Austria, the son of a taxation official. He received a doctorate from the University of Vienna in 1866 at the age of 22, completing his graduate work on a kinetic theory of gases under the supervision of Josef Stefan (1835-1893). Following his graduation, Boltzmann continued working for a short time under Stefan as an assistant before moving to Heidelberg and Berlin, where he worked under Robert Bunsen (1811-1899), Gustav Kirchoff (1824-1887), and Hermann Ludwig von Helmholtz (1821-1894).

Appointed to a chair of theoretical physics at Graz University in 1869, Boltzmann taught for four years prior to accepting a chair in mathematics at the University of Vienna in 1873. Three years later, he returned to Graz, where he stayed until 1894, this time as an experimental physicist.

His next move was to return to Vienna, where he assumed the chair of theoretical physics vacated by the death of his former advisor, Stefan. Unfortunately for Boltzmann, however, Ernst Mach (1838-1916) joined the faculty at Vienna the following year. Mach was not only a scientific rival, but the two men were on unfriendly terms, which prompted Boltzmann to leave Vienna in 1900 to move to Leipzig.

During this time, Boltzmann continued his work on statistical mechanics, running into much controversy and dispute from his colleagues. At that time, with Newtonian mechanics reigning supreme, Boltzmann claimed that the motions of gases could be better described using probability and statistics rather than by calculating the properties of every individual atom or molecule. And, furthermore, not all physicists at that time even believed in atoms or molecules, leading to further disagreement. In addition, Newtonian mechanics did not depend on a particular direction in time; that is, one could just as easily calculate motions or activities in the past as in the future. Based on this view of physics, the behavior of any substance could be calculated perfectly, given an accurate knowledge of the starting conditions. Boltzmann refused to accept this premise, arguing his points tenaciously for many years.

Bolzmann's work—independent of Scottish physicist James Clerk Maxwell (1831-1879)—led to the discovery of the Maxwell-Boltzmann distribution law concerning the energy of atoms in a gas. Boltzmann was among the first to realize the importance of Maxwell's work in electromagnetic theory. Boltzmann was also responsible for discovering the constant that bears his name. The Boltzmann constant fugures in his seminal equation which expresses the relation between entropy and probability.

The continuing attacks on his work in statistical mechanics and thermodynamics took a physical and emotional toll on Boltzmann. Always prone to mood swings, he began to feel that he was unsuccessful in defending his theories and that his life's work was to amount to nothing. Boltzmann hanged himself while on vacation in Trieste. Ironically, the experiments that were to validate his work were to take place soon thereafter.

P. ANDREW KARAM