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How a remote site on Mount Baldy played a role in measuring the speed of light

By in Press Enterprise on November 13, 2017

By Mark Landis

In the summer of 1926, an experimental beam of light pierced the night sky between two precisely measured peaks in the San Gabriel Mountains, and science history was made. Virtually unseen by the major population centers below, the beam was the key element of Dr. Albert A. Michelson’s revolutionary experiments to accurately measure the speed of light.

The light speed experiments performed in the mountains of Southern California between 1924 and 1927, were the culmination of Michelson’s remarkable 40-year career in the study of physics.

Albert Abraham Michelson was born in Strenlo, Prussia, on Dec. 19, 1852. His family immigrated to the United States in 1854, and they eventually settled in San Francisco. Michelson joined the Naval Academy at Annapolis, where he began his studies in physics. His passion was studying the velocity of light, and he went on to become a distinguished professor of physics. In 1907, Albert Michelson became the first American to be awarded the Nobel Prize in Physics.

  • Scientific Identity, Portrait of Albert Einstein and Others at Caltech, on Jan 7th, 1931. Left to Right: Walter Sydney Adams, Albert Abraham Michelson, Walther Mayer, Albert Einstein, Max Farrand, Robert Andrews Millikan (president of Caltech), unknown photographer. Date: 1931 Repository: Smithsonian Institution Libraries

  • From the National Oceanographic and Atmospheric Administration's (NOAA) Historic Coast & Geodetic Survey (C&GS) Collection

    From the National Oceanographic and Atmospheric Administration’s (NOAA) Historic Coast & Geodetic Survey (C&GS) Collection

  • Courtesy of Tom Mahood,

    Courtesy of Tom Mahood,

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Michelson spent much of his career developing new methods to measure the speed of light with increased accuracy. In the early 1920’s, he devised a plan to bounce a beam of light between two distant mountain peaks, and measure […]    

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