Percival Lowell built a private observatory in Flagstaff, Arizona. He was looking for a planet that he called Planet X. He had to prove it existed, and he was certain he would.

He tried several searches for Planet X with no success. Lowell’s first search came to an end in 1909, but in 1913 he started a second search. Lowell and others searched for this Planet X from 1913 to 1915. In 1915 Lowell published the results of his search. Unknown to him, that very same year, two small images of Planet X were recorded at Lowell’s observatory. No one would discover these pictures for another 15 years. Along with the two small images of Planet X, Lowell’s search also found 515 asteroids and 700 different stars that had never been seen before. Still, Lowell was very disappointed by his failure to find Planet X. He died the next year in 1916, never knowing that he actually DID discover the new planet.

The next search for Planet X began in April 1927. In December 1929, a young farm boy and a beginner astronomer, Clyde Tombaugh, was hired to do the search. In January 1930, he uncovered the photos of Planet X that had been taken in 1915 at Lowell’s observatory.

With the discovery of the new planet, Tombaugh needed to name it. Many suggestions were offered for naming the planet including Lowell, Apollo, Minerva, and Constance. In the end, the name finally given to Planet X was the suggestion of an 11-year-old English schoolgirl named Venetia Burney. She named Planet X - PLUTO!