Max Planck (1858-1947)
German theoretical physicist, born on 23 April 1858 in Kiel, Germany. He studied physics at the universities of Munich and Berlin, teaching at several institutions before becoming Professor of Theoretical Physics at Berlin.
In 1900 Planck introduced the hypothesis that energy is radiated in discrete bundles (called quanta) rather than continuously, as had previously been assumed. This was intended as a mathematical tool rather than as a description of the physical world, but was adopted by Albert Einstein and others, leading to the establishment of quantum physics. Planck won the 1918 Nobel Prize for his work in this field.
Planck felt it was his duty to remain in Germany under Nazi occupation. He suffered great hardship during the war: his Berlin home was destroyed and his son was executed for his part in the unsuccessful 1944 plot to assassinate Hitler. After the war the elderly Planck led efforts to reconstruct German science. He died on 4 October 1947 in Göttingen, Germany.