Clyde Tombaugh

Fifty miles west of Great Bend, down K-156 highway, is the small farm community of Burdett. In the shadow of the water tower is a roadside park with a large metal historical marker which reads:

DISCOVERER OF PLUTO Burdett is the boyhood home of Dr. Clyde Tombaugh, discoverer of the planet Pluto. Born in Illinois in 1906, he grew up on a farm northwest of here and was graduated from Burdett High School in 1925. During his youth, Tombaugh explored the heavens with homemade telescopes. Later he was hired by Lowell Observatory, Flagstaff, Arizona, and discovered Pluto, the outermost planet in our solar system, in 1930. During his planet search, Tombaugh photographed 65 percent of the sky and spent 7,000 hours examining about 90 million star images. Besides Pluto, his discoveries included six star clusters, one cloud of galaxies, one comet and about 775 asteroids. Few astronomers have seen so much of the universe in such minute detail. Dr. Tombaugh earned degrees from the University of Kansas and Northern Arizona University. He concluded his career as an astronomy professor at New Mexico State University.

Clyde Tombaugh was born in 1906 in Streator, Illinois. In 1922, his family moved to a farm near Burdett. As a youngster his interest in astronomy was encouraged by his father and uncle. Tombaugh was a self-taught amateur astronomer who made his own telescopes from hand ground mirrors and parts of farm equipment. In 1928, Tombaugh made a nine-inch telescope which enabled him to make very accurate and detailed sketches of Jupiter and Mars. Seeking advice from professional astronomers, he sent his sketches to the Lowell Observatory in Flagstaff, Arizona. As coincidence would have it, the Lowell staff was looking for an amateur astronomer capable of operating their new photographic telescope. They were sufficiently impressed with his work to offer Tombaugh the position on a trial basis.

Like many farm folk of that time, Tombaugh had never traveled very far from his home. In early January of 1929 he boarded a train for Flagstaff, Arizona. Tombaugh wrote:

After spending 28 hours in a chair car on the Santa Fe, I arrived at Flagstaff in the early afternoon of 15 January, 1929. Dr. Slipher met me at the depot and drove me up Mars Hill. The yellow pine forest was in stark contrast to the treeless plains of Western Kansas. I was rather unnerved by it all, everybody were strangers, 1,000 miles from home, and not enough money in my wallet for a return ticket home . . .

Little did he know that the three-month trial period would turn into thirteen years at the Lowell Observatory.

Prior to 1781 everyone knew that the solar system was composed of six planets. In March of that year William Herschel became the first person in recorded history to discover a planet. The discovery of Uranus was a glorious achievement for astronomy, however, there was a small problem. Uranus did not seem to want to conform to the Laws of Newtonian Physics. The planet's behavior defied predictability, and no one seemed to be able to explain this erratic behavior. In 1824, Friedrich Bessel of Germany suggested that another planet beyond Uranus would explain the problem. By 1830, it had become generally accepted that another, yet undiscovered, planet existed. Finally, on September 23, 1846, the planet Neptune was discovered by Johann Galle at the Berlin Observatory.

Neptune helped to explain the difficulties in predicting the orbit of Uranus and vindicated Newton's Laws -- sort of. There still existed a couple of minor problems, but this time almost everyone agreed that there must be another planet beyond Neptune which would explain the difficulties. Unfortunately, it was too distant, too dim, and probably impossible to find.

Enter Percival Lowell. Lowell was born into a wealthy Boston family and attended Harvard. He became a very successful businessman and traveled extensively. He eventually turned to a serious pursuit of astronomy and in 1894 he built the Lowell Observatory at Flagstaff, Arizona, so he could study the planet Mars. In 1905 Lowell began his search for the ninth planet, which he labeled "Planet X." By 1908, another American, William Pickering, was also engaged in the quest to find the mysterious planet. Pickering had helped Lowell establish his observatory but had distanced himself from Lowell after Lowell became convinced that intelligent life existed on Mars. Sadly, Percival Lowell suffered a massive stroke and died on November 12, 1916, without sighting the planet he had devoted many years to locating.

Lowell left an endowment of over a million dollars to keep his observatory operating. In his will he named his assistant, Vesto Slipher, director of the observatory. Lowell's widow contested the will, and the court battle to settle the estate--which would consume most of the endowment--lasted until 1927. Slipher prepared to resume the quest for Planet X by having a new and more powerful telescope installed. It would be a tedious task involving spending long hours in the unheated dome taking exposures of the sky and then trying to detect a minute shift in one of the thousands and thousands of points of light which would identify a planet. This is the task the observatory hired Tombaugh to perform.

To detect the movement of a object in the sky involved taking two photographs of the same section of the sky several days apart. The plates are then placed in a device called a blink comparator which "blinks" back and forth between the two plates at a speed that makes the two appear as one. Any object that has moved between the frames would be the elusive planet. Each photographic plate could contain over a 150,000 stars, and those taken of the Milky Way could contain close to a million. It took Tombaugh up to a week to examine each pair of exposures.

On February 18, 1930, Tombaugh was examining a pair of plates taken in mid-January when he noticed a shift of position by a faint star. He knew he had found Planet X. The observatory staff watched the star for a few weeks to confirm the movement, and on March 13, 1930, the discovery of the ninth planet was officially announced. Front page headlines around the world heralded the discovery. The name for the new planet was suggested by a young schoolgirl from England. She thought that because the planet was so far away from the sun and in its own dark world, it should be named for the Greek god of the underworld, Pluto.

Research Sources Available at the KSHS Center for Historical Research

Call numbers for materials at the Center are in brackets [ ]. This is only a partial listing of the materials available. Please check the catalogs for more references.

Primary Sources:

Tombaugh, Clyde W., and Patrick Moore. Out of the Darkness: The Planet Pluto. Harrisburg, Pa.: Stackpole Books, 1980. [K 523.482 T591]

Tombaugh, Clyde W. "Reminiscences of the Discovery of Pluto." Reprint of an article from Sky and Telescope, 19, no. 5 (March 1960). [K B T591 Pam.v.1 no.1]

Newspaper Articles in "Astronomy," Clippings: vol. 1-2 [K 520 Clipp.]. See also "Pawnee County," Clippings: vol. 1-2 [K 978.1 -P28 Clipp.]. Numerous and assorted newspaper articles and clippings about Tombaugh.

Davis, Watson. "Discovery of the Ninth Planet," Current History, 32 (May 1930): 337-39. [GL 051 C93 v.32]

Rath, Ida Ellen. Boy Planet Seeker. Dodge City, Kans.: Rollie Jack, 1963. [K B T591b]

Rath, Ida Ellen. The Star That Did Not Twinkle. San Antonio, Tex.: Naylor, 1963. [K B T591]

Reeder, Daniel L. "The Search for Planet X," University of Kansas Alumni Magazine, April 1980, 1-3. [SP 377.8 T G76 v.78 no.7]

Wallace, Ralph. "Adventurer of the Skies," Reader's Digest, August 1944, 37-40. [GL 051 R227 v.45 no.268]

These are sources that may be available at your school library, public library, or through interlibrary loan.

Secondary Sources:

Levy, David H. Clyde Tombaugh: Discoverer of Planet Pluto. Tucson, Ariz.: University of Arizona Press, 1991. ISBN: 0816511489.

Wetterer, Margaret. Clyde Tombaugh and the Search for Planet X. Minneapolis, Minn.: Carolrhoda Books, 1996. ISBN: 0876148933.

Clyde Tombaugh authored several articles and other publications which may be found in different scientific journals. Most of these are of a very technical nature, but may be useful in research and some of which may be found on the Internet. Other material of a biographical and general nature about Tombaugh is also available on the Internet. Key word suggestions: "Clyde Tombaugh," or "Planet Pluto" or "Pluto." A copy of the original announcement of the discovery may be found at http://www.jpl.nasa.gov/ice_fire/s_dscvry.jpg.

This guide was prepared by Michael Keil, 1998 Lela Barnes intern in the Kansas Historical Society's Library & Archives Division. For information on internships offered by the society, email David Haury or contact him at 785-272-8681, ext. 209.