Clyde Tombaugh — American astronomer who discovered Pluto

Early life and training

Born and raised on a farm in Kansas, Tombaugh was largely self-taught in observational astronomy during his youth. He built his own telescopes and sent drawings and observations to professional astronomers, which led to his employment at a major observatory. He later completed formal studies in astronomy at the University of Kansas and continued observational work throughout his career.

Discovery and method

Tombaugh's discovery began with systematic sky surveys photographed on glass plates. By viewing pairs of plates in rapid succession with a blink comparator he could detect faint objects that shifted position against background stars. The newly found body was given the name Pluto, a name proposed by a schoolgirl and accepted by the astronomical community.

Later career and contributions

After the discovery, Tombaugh remained professionally active in astronomy: he observed minor planets, variable stars and contributed to planetary studies. He worked at observatories, taught, and performed optical and astronomical research for government programs. His careful observational techniques influenced mid-20th-century planetary astronomy.

Legacy and notable facts

• Pluto was reclassified as a dwarf planet by the International Astronomical Union in 2006, altering the context of Tombaugh's discovery but not its historical importance.
• Tombaugh is remembered for combining skilled manual observation with patient systematic surveying — a practice foundational before the digital age of astronomy.
• A symbolic portion of his ashes was carried aboard the New Horizons mission to Pluto, reflecting his lasting connection to the object he first identified.

Tombaugh's life exemplifies how curiosity, self-education and careful technique can lead to discoveries that reshape our picture of the solar system. His work remains a touchstone in the history of planetary exploration.