Pluto and the Farm Boy from Kansas

Percival Lowell was rich, Harvard-educated, and obsessed with the idea that a ninth planet existed beyond Neptune. He called it Planet X. He built his own observatory on a hill above Flagstaff in eighteen ninety-four, choosing the site for its dark skies and thin dry air. He spent the last years of his life searching for Planet X and died in nineteen sixteen without finding it.

Thirteen years later, his observatory hired a twenty-three-year-old from Kansas named Clyde Tombaugh who had no college degree.

Tombaugh had grown up on a farm in western Kansas. He had built his own telescopes from farm equipment parts, grinding the mirrors himself because he could not afford to buy them. He sent drawings of Jupiter and Mars he had made through his homemade instruments to the Lowell Observatory in Flagstaff, and the observatory's director, impressed, offered him a junior assistant position. The pay was ninety dollars a month. The job was to search the sky for Planet X using a device called a blink comparator, which alternated rapidly between two photographic plates of the same sky region taken days apart. A planet would appear to move; a star would not.

On February eighteenth, nineteen thirty, Tombaugh was examining plates he had taken six days apart. One point of light moved. He checked and rechecked. He walked down the hall to the director's office and said, I have found your Planet X.

The discovery was announced on March thirteenth, the anniversary of Lowell's birthday and of William Herschel's discovery of Uranus. A flood of name suggestions arrived at the observatory. An eleven-year-old girl in Oxford named Venetia Burney wrote to her grandfather suggesting the name Pluto, for the god of the underworld. The grandfather passed the suggestion along. It was adopted.

Tombaugh continued working in astronomy for decades. He died in nineteen ninety-seven. Nine years later, the International Astronomical Union reclassified Pluto as a dwarf planet. The Kansas farm boy's discovery was the same object it had always been. The category changed around it.