description William Wallace Campbell Overview
William Wallace Campbell was an early 20th-century American astronomer and director of the Lick Observatory in California. He was a pioneer in the field of astronomical spectroscopy, specifically in the use of spectrographs to accurately measure the radial velocities of stars. His observational work also contributed to the understanding of planetary atmospheres, notably proving that the atmosphere of Mars was incredibly thin. Campbell later served as the president of the University of California system and the National Academy of Sciences.
help William Wallace Campbell FAQ
What did William Wallace Campbell discover by measuring stellar radial velocities?
Campbell used spectroscopy to measure whether stars were moving toward or away from Earth. His work at Lick Observatory also revealed hundreds of spectroscopic binary stars whose companions could not be separated visually.
How did Campbell's spectrographs measure a star's motion?
He compared shifts in a star's spectral lines with their known laboratory wavelengths. A shift toward blue indicated approach, while a shift toward red indicated recession along the observer's line of sight.
What was Campbell's role at Lick Observatory?
Campbell joined Lick Observatory in 1891 and became its director in 1901. He developed Lick into an important center for stellar spectroscopy and organized observations from both California and the Southern Hemisphere.
Did William Wallace Campbell help test Einstein's theory of relativity?
Yes. Campbell led a Lick Observatory expedition to Australia for the 1922 total solar eclipse, where photographs were used to measure the deflection of starlight near the Sun predicted by Einstein.
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