Article first published in Vol. 25 (2006-2007)
By Elva R. O'Hara
By day he worked the Kansas fields. By night he explored the heavens with a homemade telescope. Without a college education or scientific support, Clyde W. Tombaugh made unparalleled contributions to the field of astronomy in the 20th century, the most well known being his discovery of the planet Pluto.
Tombaugh was born on Feb. 4, 1906, in Streator, Ill. He might have been a typical farm boy but for his one fascination: astronomy. Through the influence of his father and an uncle, the 12-year-old Tombaugh began observing the night sky. He spent hundreds of hours using a 9-inch telescope bought at Sears and Roebuck, learning to methodically identify stars and constellations as well as to observe the movements of the planets.
Image caption: Clyde W. Tombaugh shared a homemade telescope with his father and uncle. Photo courtesy of NMSU Library Archives and Special Collections
The family moved to a farm in Burdett, Kan., in 1922. While maintaining his responsibilities on the farm, he taught himself from his father's books of trigonometry, physics, Latin and Greek. He read everything on astronomy that he could find. At 16, Tombaugh had to drop out of high school for a year to help prepare the family's farm for the fall seeding of wheat.
Unable to buy a more powerful telescope, Tombaugh decided to build his own. With advice from experts with whom he had begun corresponding, Tombaugh learned to perfect the process of grinding and polishing mirrors for his own telescope, a 9-inch Newtonian reflector. He used mirrors that he ground himself throughout his life.
The self-educated Tombaugh longed for a college education in the field of astronomy. In 1928 when he was 22, the crop yield that was supposed to pay for college was ruined by a 20-minute hailstorm. Despite this devastating turn of events, Tombaugh began making precise, detailed drawings of the markings on Jupiter and Mars.
Tombaugh had read observation reports about Mars which were written by the staff of Lowell Observatory in a 1924 issue of Popular Astronomy. He sent his drawings of Jupiter and Mars to Dr. V. M. Slipher , director of the observatory in Flagstaff, Ariz. Slipher was impressed by the precision of his drawings and hired him to operate their new 13-inch photographic telescope. Without a college degree or established credentials as an astronomer, Tombaugh began his career at Lowell Observatory in January 1929, an association lasting 14 years.
Dr. Slipher assigned Tombaugh to work in the dome operating the new telescope in search of the much hypothesized “Planet X.” Based on the discoveries of the planets Uranus and Neptune, astronomer Percival Lowell, founder and first director of Lowell Observatory, had predicted the discovery of Planet X in his Memoir on a Trans-Neptunian Planet published in 1915. Lowell died in 1916, still looking for Planet X. Tombaugh began taking photographic plates on April 6, 1929.
Tombaugh discovered what was thought to be the “trans-Neptunian” planet on Feb. 18, 1930. He was just 24. The planet was named in April 1930. Tombaugh said that because Pluto, two-thirds the size of Earth's moon, is so far from the sun, it was decided by the staff of Lowell Observatory to name the planet after Pluto, the Roman god of the underworld associated with darkness.
Tombaugh's discovery created a sensation worldwide. In a March 14, 1930, New York Times interview, Tombaugh humbly attributed the discovery of the planet to “running another bunch of photo plates through the machine” and that he was “just lucky.” Although he had gained international fame, he returned to the farm that summer on vacation and was found helping his father harvest wheat.
Tombaugh was finally able to realize his dream of attending a university when he entered the University of Kansas in 1932, thanks to a scholarship that the Burdett High School principal arranged for the hometown hero. He received his B.A. in astronomy in 1936 and an M.A. in the same field in 1939. Tombaugh related that initially, the astronomy professor would not allow him to enroll in the astronomy class because he had already discovered a new planet and perhaps his presence would be “disconcerting.”
While in college, Tombaugh married Patricia Edson, a student whose brother also was in astronomy. The couple, along with their friends, formed a club to discuss astronomy, including space exploration and extraterrestrial life. The couple had two children, Annette and Alden.
Tombaugh's years of studying the photographic plates at Lowell also resulted in discoveries of two comets, hundreds of new asteroids, new star clusters, a superstar cluster and variable stars. Most important was his study of about 30,000 galaxies, more than 20 times the number then known. He refuted Edwin Hubble's theory that galaxies were evenly distributed across the sky. Tombaugh's observations proved that 95 percent of galaxies belonged to clusters. The young amateur astronomer also published his findings, despite the fact that he had no Ph.D., and the famous astronomer Hubble had dismissed Tombaugh's findings.
During his scientific career, Tombaugh greatly contributed to the defense of our country. He taught navigation during World War II at Arizona State Teacher's College (now Northern Arizona University) and developed tracking systems at the Ballistics Research Lab at White Sands Proving Ground from 1946 to 1955. One instrument, a “super camera” that he designed while at White Sands, was used for 30 years before being replaced.
In 1955, he moved to what is now New Mexico State University. He taught geology and astronomy at NMSU, helping to develop a department of astronomy. NMSU dedicated its observatory to Tombaugh in 1972. Retiring in 1973, he was named Professor of Astronomy Emeritus. He received an honorary doctorate from Northern Arizona University and had an elementary school in Las Cruces named for him, among many other tributes.
Tombaugh lectured across the United States and Canada for four years to raise money for a post-doctorate scholarship in astronomy at NMSU named for him. His efforts raised almost $500,000.
In 1991, Tombaugh was inducted into the Academy of Achievement based in Washington, D.C., which gathers contemporary leaders who “represent the pinnacle of achievement in their respective fields.” In an interview with the Academy, Tombaugh stated, “I studied solid geometry and trigonometry on my own because they didn't offer those in high school at that time. Can you imagine young people nowadays making a study of trigonometry for the fun of it? Well, I did.”
Tombaugh died on Jan. 17, 1997, just before he turned 91. In the February 2006 issue of Astronomy, Dan Falk wrote that in recent years, Tombaugh's discovery of Pluto had become controversial as scientists questioned its status as a planet. Pluto now is recognized as the brightest of the objects in the Kuiper Belt, a ring of thousands of small frozen entities which orbit the sun far beyond Neptune's orbit. In 2005, one of these bodies was discovered to be about 250 miles larger than Pluto.
In 1978, Pluto's moon Charon was discovered by James Christy. In 2005, two much smaller moons were discovered and have been named Hydra and Nix. On Jan. 19, 2006, NASA launched the New Horizons spacecraft on a 3 billion-mile trip to Pluto. The probe is calculated to reach Pluto in 2015, when it is to photograph and analyze Pluto's atmosphere and send data back to Earth. It will also map in detail the two new moons. Aboard the spacecraft are some of Tombaugh's ashes, a gesture saluting his love of space exploration.
Tombaugh's widow Patricia, 93, and other family members attended the launch at Cape Canaveral, Fla. On the New Horizons website, Patricia Tombaugh said, “I always had to share Clyde not only with Mars, Jupiter, the Moon, and stars, but also with the public. … He once said that he had received at least 30,000 letters. He tried to answer each one.”
On August 24, 2006, the International Astronomical Union (IAU) voted to downgrade Pluto to “dwarf planet” status, reducing the number of “true” planets to eight. On the online NMSU hotline, Jim Murphy, Head of the Department of Astronomy at NMSU, said, “This reclassification indicates how ahead of its time Pluto's initial detection actually was. … It was 73 years before a comparable sized object was discovered, using technology that was greatly enhanced over that available in 1930. The NMSU Department of Astronomy is and always will be proud of its history with Clyde Tombaugh and his family and will always hold his accomplishments in the highest esteem. Long live Pluto and its sibling 'dwarf planets'!”
The IAU's decision, made by only 10 percent of its members, was met with disappointment and protest in many parts of the world, including Las Cruces, where dozens of people marched while holding signs declaring “Size Doesn't Matter” and “Protest for Pluto.” Tombaugh's wife also sympathized with children who would be disappointed. In a Los Angeles Times article, she was quoted as saying children love Pluto because “It's little, like they are.” A petition is circulating among international astronomers protesting the IAU's definition of a planet, which says a true planet must “clear the neighborhood of its orbit.” Pluto's oblong orbit overlaps that of Neptune.
Tombaugh was aware of the debate over his discovery, but his biographer David Levy said that Tombaugh's legacy is intact and his major achievement is that “he opened the door to the outer part of the solar system.”
Regardless of Pluto's status, Clyde Tombaugh proved that dreams can be fulfilled by reaching for the stars.
Tags: Biography
