Max Planck

Max Karl Ernst Ludwig Planck was born on April 23, 1858, in Kiel, then part of the Duchy of Holstein. He came from an academic family with a tradition of scholarship in law and theology. He studied physics at the University of Munich and the University of Berlin, where he was influenced by Hermann von Helmholtz and Gustav Kirchhoff. He received his doctorate from Munich in 1879 with a thesis on the second law of thermodynamics.

Planck was appointed professor of theoretical physics at the University of Berlin in 1889, where he remained for most of his career. During the 1890s, he devoted intensive work to the problem of blackbody radiation: classical physics predicted that a blackbody should emit infinite energy at high frequencies, a result so clearly wrong it became known as the ultraviolet catastrophe.

In October 1900, Planck presented an empirical formula that correctly described the blackbody radiation spectrum. To derive a theoretical justification for this formula, he was compelled in December 1900 to introduce a radical assumption: that energy is not continuous but is emitted and absorbed in discrete packets, which he called quanta. The mathematical relationship involved a new fundamental constant, now universally known as Planck's constant (h), with the value approximately 6.626 x 10^-34 joule-seconds.

Planck himself viewed this hypothesis with ambivalence, hoping it might eventually be reconciled with classical physics. It was Albert Einstein's 1905 explanation of the photoelectric effect using quanta that demonstrated the physical reality of Planck's insight and extended it beyond thermal radiation. The quantum hypothesis subsequently became the foundation of an entirely new physics.

In 1918, Planck received the Nobel Prize in Physics for the discovery of energy quanta. He served as president of the Kaiser Wilhelm Society from 1930 to 1937 and worked to protect scientific institutions during the rise of National Socialism, with limited success.

Planck's later years were marked by profound personal tragedy: his first wife died in 1909, one son was killed in World War I, and twin daughters died in childbirth. His son Erwin was executed in 1945 for alleged involvement in the July 1944 plot against Hitler.

Max Planck died on October 4, 1947, in Göttingen. The Max Planck Society, Germany's foremost research organization, was named in his honor in 1948.