American astrophysicist (1868–1938)

Hale's father, William Hale, was a wealthy manufacturer of elevators in Chicago, Illinois, who stimulated in his son an early interest in designing and making his own instruments. This interest was directed to astronomy by Sherburne W. Burnham, a neighbor and passionate observer of double stars, and increased during his four years at the Massachusetts Institute of Technology, where he studied physics. He built a solar observatory, financed by his father, at Kenwood, Chicago, and after graduating in 1890 became its director. In 1892 he was appointed assistant professor and later professor of astrophysics at the new University of Chicago and from 1895 to 1905 he was director of the university's Yerkes Observatory. From 1904 to 1923 he was director of the newly established Mount Wilson Observatory in California. The last 15 years of his life were spent organizing the equipping and building of the Palomar Observatory in California and in the pursuit of his solar researches in his private observatory in Pasadena.

Hale was undoubtedly one of the key figures in 20th-century astronomy. He saw very clearly and very early that astronomy could only develop if much more powerful telescopes were constructed. Thus with great vision and enormous persistence and energy he spent 40 years acting as midwife to a series of bigger and bigger telescopes. His insight was clearly justified for it was with his telescopes that Harlow Shapley, Edwin Hubble, and many others made their observations.

His first triumph came when he persuaded Charles T. Yerkes, a Chicago trolley-car magnate, to provide $349,000 to build a 40-inch (1-m) refracting telescope for the University of Chicago. This was and still is the largest refractor ever built. It was first used in 1897. He was soon anxious, however, to build a large reflecting telescope. In 1896 his father acquired a 60-inch (1.5-m) mirror but the University of Chicago was unable to fund its mounting. Hale once more started raising money. This time he interested the Carnegie Institution of Washington in financing the Mount Wilson Observatory. The observatory was founded in 1904 and the 60-inch reflector eventually went into use in 1908. In 1918 this superb instrument was surpassed by the 100-inch (2.5-m) Hooker telescope, largely financed by a Los Angeles business man, John D. Hooker. For 30 years this was the world's largest telescope and it revolutionized astronomy.

Hale had resigned from his directorship of Mount Wilson Observatory in 1923 on the grounds of ill health but lost little time in seeking to interest the Rockefeller Foundation in building a reflecting telescope that would be the ultimate in size, 200 inches (5 m) across, for Earth-based instruments. In 1929 it was finally agreed that $6 million would be donated for this purpose to an educational institute, the California Institute of Technology, rather than the Carnegie Institution. Hale became chairman of the group directing the planning, construction, and operation of the instrument that was to become his masterpiece.

Thus there began an epic struggle to complete the 200-inch telescope, which was to take nearly 20 years. The first mirror made from fused quartz proved to be a $600,000 failure. Hale next tried Pyrex and the first experimental 200-inch disk cast proved satisfactory. The actual casting was made in December 1934 when the 65 tons of molten Pyrex began its carefully controlled 10 months' cooling. The mirror managed to survive the flooding of the factory, which necessitated shutting down the temperature control for three days, and its long journey in the spring of 1936 from Corning, New York, to California at a maximum speed of 25 mph. The grinding of the mirror was interrupted by the war and took so long that Hale had been dead for nine years when the instrument was finally commissioned as the Hale telescope in 1948. It was set up at the specially constructed Palomar Observatory, which together with the Mount Wilson Observatory was jointly operated by the California Institute of Technology and the Carnegie Institution. The two observatories were renamed the Hale Observatories in 1969. The Hale telescope was the world's largest telescope until the Soviet 6-meter (236-in) reflector went into operation in 1977 but is still considered by many to be the world's finest.

Hale was not just a highly successful scientific entrepreneur for he made major advances in the field of solar spectroscopy. As early as 1889 he had conceived of his spectroheliograph, an instrument that allowed the Sun to be photographed at a particular wavelength. He also designed an appropriate telescope to which it could be attached. In 1908 Hale made his most significant observation. He found that some of the lines in the spectra of sunspots were double. He realized that this demonstrated the presence of strong magnetic fields in sunspots, being due to the effect discovered by Pieter Zeeman in 1896, and was the first indication of an extraterrestrial magnetic field.

The American astronomer George Ellery Hale (1868-1938) designed and built three great observatories, invented the spectroheliograph, and discovered magnetic fields in sunspots.

George Ellery Hale was born on June 29, 1868, in Chicago, Illinois, the eldest surviving son of William Ellery Hale and Mary Scranton Browne. His father, a wealthy elevator manufacturer, instilled in Hale from an early age a love for tools and machinery and a deep interest in public affairs. Armed with a box of tools and small lathe for turning metal, Hale transformed his bedroom into a laboratory and later built with his own hands a workshop in the yard.

Hale's mother, a graduate of the Hartford Female Seminary in Hartford, Connecticut, cultivated his literary side, reading aloud the Iliad and the Odyssey and stocking the shelves of his personal library with books ranging from the unabridged Robinson Crusoe and Don Quixote in translation to Grimm's Fairy Tales and the poetry of Shelley and Keats. In biographical notes written in 1933 Hale spoke fondly of these and other classics that "helped greatly to arouse my imagination and prepare me for scientific research."

Early Interest in Astronomy

Hale attended the Oakland Public School and later the Allen Academy, taking also a shop course at the Chicago Manual Training School. But what mattered most to Hale were the studies he worked on at home. Astronomy headed the list. He first built a small telescope, then a spectroscope. Attached to the telescope, now a 4-inch Clark refractor purchased for him by his father, the homemade instrument allowed Hale to observe the solar spectrum. In 1884 he photographed a spectrum using a small commercial spectrometer. To measure more accurately the wavelengths of the dark Fraunhofer lines in the solar spectrum, Hale added a one-inch plane grating to the single prism spectrometer.

Reading everything he could find on spectra during these years, Hale bought Norman Lockyer's Studies in Spectrum Analysis. Inspired, he began laboratory observations of spectra and compared them with those of the sun's spectrum. Out of that work was born Hale's lifelong interest in the physical properties of the sun and stars. In explaining why classical astronomy with its emphasis on determining the positions, distances, and motions of celestial bodies did not appeal to him even then, Hale later wrote:"I was born an experimentalist, and I was bound to find the way of combining physics and chemistry with astronomy."

His First Observatory

Determined to leave his mark on the young science of astrophysics, Hale entered the Massachusetts Institute of Technology (MIT) in 1886, where he studied chemistry, physics, and mathematics. For astronomy, he turned to Edward C. Pickering, director of the Harvard College Observatory, who took him on as a volunteer assistant. During summer vacations he continued his own solar and stellar research in a specially-equipped spectroscopic laboratory of his own design built for him by his father in 1888 on a lot adjacent to the family home in the Kenwood section of Chicago. This formed the nucleus of the Kenwood Physical Observatory.

At the time the standard method of recording solar prominences consisted of drawings based on visual observation. In his quest to find an adequate method of photographing prominences, Hale invented the spectroheliograph - an instrument for photographing phenomena in the solar atmosphere that would otherwise be invisible. The first tests of his new instrument, made in the winter of 1889-1890 at the Harvard Observatory, demonstrated that the basic principle was right. Then a senior at MIT, he wrote up the work for his thesis and received a B.S. in physics. Hale married Evelina Conklin in June 1890, two days after graduation. Upon their return to Chicago, Hale's father agreed to finance the construction of a 12-inch refractor telescope.

At the Kenwood Observatory, dedicated in 1891, Hale continued his experiments with the spectroheliograph. In examining the spectra of prominences, he observed two bright lines (H and K), which he had determined to be due to calcium, in the ultraviolet region. They proved ideal for photographing prominences, as photographic plates then in use were more sensitive to light in the ultraviolet. Moreover, his photographs of solar spectra showed H and K as bright lines all over the sun. Armed with this information and an improved instrument, Hale photographed these calcium clouds (flocculi) and prominences both at the solar limb and across the disc in 1892 for the first time. The success of this research tool sealed Hale's international reputation as a solar astronomer. Many of his findings appeared in Astronomy and Astrophysics, the forerunner of the Astrophysical Journal, a publication founded by Hale in 1895 and still the leading astronomical journal in the field.

Two More Observatories

In 1892 Hale joined the faculty of the new University of Chicago as associate professor of astrophysics and director of the observatory. An accomplished organizer and money-raiser, Hale persuaded streetcar millionaire C. T. Yerkes to provide the university with the largest refractor telescope in the world. Hailed in 1897 for its revolutionary design, the Yerkes Observatory at Williams Bay, Wisconsin, was, as Hale stated, "in reality a large physical laboratory as well as an astronomical establishment." There, with the aid of F. Ellerman and J. A. Parkhurst, Hale carried out a study on the spectra of low-temperature red stars (Secchi's fourth type). Besides continuing his own research on sunspot spectra, he also studied the distribution of calcium flocculi at different levels in the solar atmosphere and found the dark hydrogen flocculi using a large spectroheliograph of his own design built for the 40-inch telescope.

Hale lived by his own motto, "Make no small plans." He founded the Mount Wilson Observatory in Pasadena, California, in 1904 with funds provided by the Carnegie Institution and served as its director until 1923. In an effort to eliminate mirror distortion and air turbulence, Hale designed and built in 1908 a 60-foot tower telescope with a long vertical spectroheliograph in an underground well. By then he had discovered the low temperature of sunspots, the vortex structure of the dark hydrogen flocculi in the vicinity of sunspots, and the magnetic fields of sunspots. The discovery of hydrogen vortices around sunspots suggested to Hale that the double lines in sunspot spectra, photographed with the 60-foot tower telescope, were not due, as previously believed, to "reversals, " but rather to intense magnetic fields (the Zeeman effect).

In 1908 Hale compared his astronomical work with the similar doubling of lines obtained with large electromagnets in the observatory's physical laboratory and demonstrated conclusively for the first time the existence of sunspot magnetic fields. Working later with the 150-foot tower telescope, Hale attempted to measure the general magnetic field of the sun; he also formulated the law of sunspot polarities and discovered the reversal of sunspot polarities in successive 11-year cycles.

A solar astronomer primarily, Hale also built stellar telescopes:a 60-inch reflector installed at Mount Wilson in 1908, and a 100-inch telescope inaugurated in 1917. In 1928 the International Educational Board of the Rockefeller Foundation agreed to finance Hale's $6 million proposal to build a 200-inch telescope on Mount Palomar (dedicated in 1948, it bears his name).

A Leader in the Science Community

A scientist bursting with educational, architectural, and civic ideas, Hale was elected to the National Academy of Sciences in 1902 and promptly set about to reform it. He created (and served as first chairman) the National Research Council, the operating arm of the academy, in 1916; aided in establishing a fellowship program in 1919; and raised the endowment for the council and the construction in 1924 of a permanent building for the academy in Washington, D.C. Back in Pasadena, he joined the board of trustees of Throop Polytechnic Institute in 1906 and played a major role in transforming it into the California Institute of Technology, a distinguished school of research and teaching in science and engineering. He influenced the creation of the Henry E. Huntington Library and Art Gallery and worked on the master plan for Pasadena's civic center.

Weakened by a series of nervous breakdowns, Hale resigned as director of the observatory in 1923 and built a small solar laboratory in Pasadena, where he continued to do research on the sun. Honors received during his life-time include the Royal Astronomical Society medal in 1904 and the Copley medal of the Royal Society in 1932 and election to the Accademia dei Lincei and the Royal Society of London, as well as membership in many scientific societies in the United States and abroad. He entered Las Encinas sanitarium in Pasadena following a stroke and died there of heart trouble on February 21, 1938.

Further Reading

Novelist Theodore Dreiser wrote Hale into his novel about Charles Yerkes, The Titan (1914). A first-hand account of Hale's work in California appears in Ten Years' Work of a Mountain Observatory (1915). The only full-length biography of Hale is Helen Wright, Explorer of the Universe (1966). Walter A. Adams, who succeeded Hale as director of the Mount Wilson Observatory, leaned heavily on Hale's unpublished autobiographical notes in the biographical introduction he prepared for the NAS Biog. Mem. (1940). Hale published six books and over 450 articles, all of which are chronologically listed in Adams' bibliography. Hale's work in astronomy and in developing scientific institutions is vividly revealed in pictures, documents, and essays in Helen Wright, Joan N. Warnow, and Charles Weiner (editors), The Legacy of George Ellery Hale (1972). Good background material is in Owen Gingerich (editor), Astrophysics and Twentieth-Century Astronomy to 1950:Part A (1984) and in Daniel Kevles, The Physicists (1978).

Additional Sources

Osterbrock, Donald E., Pauper & prince:Ritchey, Hale & big American telescopes, Tucson:University of Arizona Press, 1993.

Wright, Helen, Explorer of the universe:a biography of George Ellery Hale, Woodbury, N.Y.:American Institute of Physics, 1994.

For more information on George Ellery Hale, visit Britannica.com.

1868–1938, American astronomer, b. Chicago, grad. Massachusetts Institute of Technology, 1890. He founded and directed three great observatories (Yerkes, Mt. Wilson, and Palomar), each in its time the greatest in the world, and was active in organizing interdisciplinary scientific societies nationally and internationally. In 1895 he founded the Astrophysical Journal, which remains the leading publication in its field. He had a unique talent for raising funds from private sources in the days before massive governmental support of scientific research. The 200-in. (508-cm) reflector at Palomar Mt. is named the Hale telescope in his honor, and the Mt. Wilson and Palomar observatories were renamed (1969–86) the Hale Observatories. In his own work he pioneered the experimental study of the physical nature of the sun and stars. His observatories were also laboratories employing the latest in photographic and spectrographic techniques. In 1890 he invented the spectroheliograph, which led to the discovery of magnetic fields and vortices in sunspots. Although he studied in Germany with Helmholtz and Planck, served as the first professor of astrophysics at the Univ. of Chicago, and received many prizes and medals from scientific academies around the world, he never completed the requirements for his Ph.D. Besides technical monographs, he wrote popular books, including Depths of the Universe (1924), Beyond the Milky Way (1926), and Signals from the Stars (1931).

Quotes:

"Like buried treasures, the outposts of the universe have beckoned to the adventurous from immemorial times..."

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