Thursday, March 22, 2007

The Pulse of the Universe

Robert Millikan was born on this day in 1868 in Morrison, Illinois.

Robert Millikan was at the forefront of the awakening of U.S. physics around the turn of the 20th century, both as a researcher and educator. While a student at Oberlin College, with no previous experience he was pressed into service by his Greek professor to teach physics; when he protested that he didn't know anything about physics, his Greek professor simply insisted that anyone who could master Greek could master physics -- such was the American view of physics as a static, classical discipline at the end of the 19th century.

Nevertheless, the advice propelled Millikan into his life's work. He later studied at Columbia, graduating as the school's only physics Ph.D. in 1893, and went to Germany to study with Max Planck. He returned to the U.S. in 1896 to teach physics at the University of Chicago, where he devoted half of his time to research. In 1909, Millikan succeeded in measuring an electric charge by suspending a tiny oil drop in an electric field, then measuring the strength of the field. He discovered that an electric charge (e) can only be found in integer multiples of a fundamental "piece" of charge, thus demonstrating the atomic nature of electricity. For this work in 1923 Millikan became only the second American to win the Nobel Prize for Physics (the first being the chair of his department at Chicago, Albert A. Michelson).

Between 1912 and 1915, Millikan experimentally verified Albert Einstein's predictions about the photoelectric effect, providing a photoelectric determination of the value of Planck's constant (h) in the process. For the first time in the 20th century, through Millikan's work American physics was having an impact on the leading-edge crosscurrents of European physics. In the 1920s, he began to study the region of the spectrum between the ultraviolet and X-radiation, extending the knowledge of the ultraviolet spectrum downwards far below what was previously observed. He also discovered a law of motion regarding the falling of a particle towards the Earth after entering the Earth's atmosphere, which led to his study of radiation in the atmosphere, previously thought to have resulted from radioactive elements on Earth.

In 1927, Millikan appeared on the cover of Time as the man who had "detected the pulse of the universe" after he coined the phrase "cosmic rays" (to the delight of sci-fi writers everywhere) to describe radiation in the atmosphere which could only come from outer space, as his experiments demonstrated. Initially, Millikan believed that these rays were "birth cries" (i.e. energy) from infant atoms being formed in outer space, perhaps by the Creator who was "continually on his job," but he later retreated from the position as the scientific community failed to rally to the hypothesis. Nevertheless, Millikan was passionate about harmonizing science and religion, and was a frequent speaker on the subject; some critics joked that they couldn't tell the difference between the two by the time Millikan was through with them.

America's most popular scientist, he was particularly admired by the U.S. industrial community, much of which applauded the anti-New Deal, Herbert Spencer-style determinism which laced his speeches, a circumstance which served him well in raising funds for the California Institute of Technology as head of the physics department from 1921 to 1946. He died on December 19, 1953 in San Marino, California.



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