On February 18, 1930, Clyde Tombaugh discovered a possible moving object after nearly a year of searching. He did this by taking images of the night sky taken two weeks apart and then examine them for differences. The photos taken on January 23 and 29 of 1930, combined with a low-quality photo from January 21 confirmed the movement of the distant planet.
The Lowell Observatory reserved the right to name the new object and received over 1,000 suggestions from all over the world. The name Pluto came from the god of the underworld, which was proposed by an 11-year-old schoolgirl in Oxford, England.
Pluto's orbital period is 248 Earth years, with a chaotic, highly inclined orbit that differs from the rest of the planet. A single day on Pluto, or the time it takes to complete a rotation, is 6.39 Earth days, rotating at an axial tilt of 120-degrees.
