In 2006, the International Astronomical Union demoted Pluto to one of dozens of dwarf planets. After its discovery in 1930, Pluto was declared the ninth planet in our solar system and quickly ...

"Tombaugh sent some of his drawings off to different places ... roughly where Lowell had predicted it would be. A ninth ...

Discovered in 1930, Pluto was the ninth planet for over 75 years, orbiting at the chilly fringes of our solar neighborhood. But then scientists at the International Astronomical Union decided ...

At just 23 years old, Tombaugh sent his drawings, unsolicited ... the discovery of a new planet. The search for Pluto did not begin with Clyde Tombaugh, to be fair. That distinction belongs ...