Saturday, April 26, 2008

Max Planck, Founder of Quantum Theory

Max Planck was born on April 23, 1858 in Kiel, Holstein, Germany. One of the most important physicists of the twentieth century, he is best known today for the constant which bears his name, the Planck Constant, a key component of the Quanta Theory. His life is an amazing mix of greatness and tragedy.

For starters, he demonstrated his genius at high school, where mathematician Hermann Müller taught him astronomy, mechanics and mathematics. He graduated early, at age 17. His physics professor advised Planck that everything important had already been discovered. Fortunately, he ignored this advice and began his studies in 1874 at the University of Munich.

In April 1885 he became an associate professor of theoretical physics at the University of Kiel. Two years later he married Marie Merck, they had four children (Karl, Emma, Grete and Erwin). 1892 he finally became a full professor.

In 1894 Planck turned his attention to the problem of black-body radiation. It was still a mystery why the intensity of the electromagnetic radiation emitted by a black body depends on the frequency of the radiation and the temperature of the body.

In 1900 he finally proposed his solution, claiming that electromagnetic energy could be emitted only in quantized form - the quantum theory was born.Energy can only be a multiple of an elementary unit E = h ν, where h is Planck's constant and ν is the frequency of the radiation.

The discovery of Planck's constant enabled him to define a new universal set of physical units (such as the Planck length and the Planck mass ), all based on fundamental physical constants. In 1905 the completely unknown Albert Einstein published his articles in a physics journal. Planck was among the few who immediately recognized the significance of the special theory of relativity. Thanks to his influence, this theory was soon widely accepted in Germany.

In July 1909, Marie Planck died; two years later, he married his second wife, Marga von Hoesslin. They had one child (Herrmann Planck). During the First World War Planck's oldest son, Karl, was killed in action at Verdun, and Erwin was taken prisoner by the French in 1914. Grete died in 1917 while giving birth to her first child.

Meanwhile Planck had been appointed dean of Berlin University, whereby it was possible for him to call Einstein to Berlin and establish a new professorship for him. Soon the two scientists became close friends and met frequently to play music together.

During the First World War Planck signed the infamous " Manifesto of the 93 intellectuals ", a polemic pamphlet of war propaganda, while Einstein retained a strictly pacifistic attitude which almost led to his imprisonment. In 1915 Planck revoked parts of the Manifesto, and in 1916 he signed a declaration against German annexationism.

In 1918 Max Planck was awarded the Nobel Prize in Physics for his discovery of the Quantum Theory, the most successful physical theory of all times.When the Nazis seized power in 1933, Planck was 74. He was criticized for teaching Einstein's Relativity Theorems; and the Nazis started to investigate Planck's ancestry. At the end of 1938 the Prussian Academy was taken over by Nazis, Planck protested by resigning his presidency.

In January 1945 his second son, Erwin, was executed by the Gestapo because of his participation in the failed attempt to assassinate Hitler in July 1944.

Max Planck died shortly after the end of the war on October 4, 1947.

Following extract is from Einstein's Tribute to Max Planck ".... many kinds of men devote themselves to science and not all for the sake of science herself. There are some who come into her temple because it offers them the opportunity to display their particular talents. To this class of men, science is a kind of sport in the practice of which they exult, just as an athlete exults in the exercise of his muscular prowess. There is another class of men who come into the temple to make an offering their brain pulp in the hope of securing a profitable return. These men are scientists only by the chance of some circumstance which offered itself when making a choice of career. If the attending circumstances had been different they might have become politicians or captains of business . Should an angel of God descend and drive from the temple of science all those who belong to the categories I have mentioned, I fear the temple would be nearly emptied. But a few worshippers would still remain -- some from former times and some from ours. To those latter belong our Planck. And that is why we love him."

Source doct: The World Treasury of Physics, Astronomy, and Mathematics, edited by Tim. Ferris, page 590.


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