a tiny moving speck against the starry background, roughly where Lowell had predicted it would be. A ninth planet, Pluto, had ...

Pluto was discovered in 1930 in Arizona, but in 2006 scientists decided to cut Pluto from the planetary line up. Here is why Pluto isn't a planet.

Nevertheless, because it orbited the Sun like a planet, it was classified as a planet and named Pluto, after the god of outer darkness in Roman mythology. So things stood for 65 years. Although ...

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 ...