Sir William Huggins | Biography

William Huggins, born in London, England, on February 7, 1824, went from looking through the eyepiece of a microscope to that of a telescope.

Huggins was intrigued with the concept of spectroscopy developed by Gustav Kirchhoff, and fully realized its use for astronomy. While it is impossible to place a piece of star under a microscope for study, it is possible to analyze the light given off by a star. With his friend, W. A. Miller, Huggins built his own observatory in 1856 and eagerly studied every source of light he could.

In 1863 he made the astounding announcement that the spectra of stars revealed the same elements as those on the Earth. For example, when Huggins noticed that the lines of a star's spectrum matched those of the spectral lines of oxygen on earth, he concluded that there was oxygen in that star. This disproved the hypothesis made by Aristotle 2,100 years earlier that the heavens were made of a unique material not found on the earth.

Looking at the spectrum of a nebula in Draco, Huggins learned that it was composed of glowing gases--not of stars, as was suspected of all nebulae before his observation. He studied the spectrum of a nova in 1868 and found that it was surrounded by hydrogen. The spectrum of a comet revealed carbon compounds. He was not successful with all his observations; he could draw no conclusions about the spectra of the planets (which, of course, turn out to be spectra of reflected sunlight).

Huggins was also among the first to use photography to "collect" light. While the eye can respond only to light entering it at a given moment, a long time-exposure photograph allows light from faint objects to collect, resulting in a much brighter image. Huggins used time exposures to enhance the visibility of the spectra of extremely dim objects. The photographic plate also allowed Huggins to make permanent records of his observations.

Furthermore, Huggins applied the Doppler effect to the analysis of his spectra. If a star is moving toward an observer, the wavelengths of light in its spectrum should be shifted toward the blue end of the spectrum; if moving away it should be stretched out toward the red end. In 1868 he found that the star Sirius, the brightest star in the night sky, had a slight shift in one of the hydrogen lines toward the red end of the spectrum. He concluded that Sirius was moving away from the Earth, and that the amount of the red shift corresponded to its velocity.

As long as the spectrum of an object can be obtained, however distant it may be, its movement and composition can be determined. Analysis of the spectral shifts of objects would be fundamental for Edwin Powell Hubble's conclusions about the structure of the universe in 1929.