Answer: Clyde Tombaugh
In the 1930s a young astronomer named Clyde Tombaugh was tasked with the job of searching the outer reaches of the solar system for the elusive Planet X. Astronomers of the day were confident there was an additional planetary body just beyond the orbit of Neptune. After comparing photos taken at Lowell Observatory in Flagstaff, Arizona, Tombaugh and his colleagues confirmed the object in question was indeed a planet and not an asteroid or another deep-space object.
The tiny planet was named Pluto as the result of a contest—an11-year-old English student, Venetia Burny, suggested Pluto because the Roman god of the underworld was able to render himself invisible and was elusive much like the planet in question. Although Clyde Tombaugh discovered and studied hundreds of asteroids, stars, and galaxy clustered, and even a galaxy super cluster, he remains best known for discovering Pluto.
Tombaugh passed way in 1997, but his adventures in deep space studies hardly ended there. In 2006, NASA launched the New Horizons Space Probe. The probe is destined to flyby Pluto in 2015 as part of its research mission. Aboard the probe are the ashes of Clyde Tombaugh, ensuring Tombaugh will enjoy the closest encounter any astronomer has ever had with the celestial body they discovered.