He called this hypothetical world "Planet X." "In some ways, Pluto's more of a planet than some of the other established planets, like Mercury." ...

He called this hypothetical world "Planet X." "In some ways, Pluto's more of a planet than some of the other established planets, like Mercury." Lowell dedicated years to predicting the location ...

Pluto was discovered at Lowell Observatory in Flagstaff, Arizona in 1930 and was considered our ninth planet until 2006. The International Astronomical Union reclassified Pluto as a dwarf planet ...

If you answered "Pluto's planethood," your grasp of the astronomical is excellent. Feb. 18 marks the 95th anniversary of the discovery of our outermost planet-not-planet. Here's what to know about ...

Prague, CZECH REPUBLIC: Members of the International Astronomic Union (IAU), vote on the Resolution for Planet Definition 24 August 2006 in Prague. The resolution demoted Pluto from its status as ...

Pluto, discovered in 1930, was once considered the ninth planet in our solar system. In 2006, the International Astronomical Union reclassified Pluto as a dwarf planet because it doesn't meet all ...

They did, and the discovery of Planet X was announced on March 13, 1930. An 11-year-old English schoolgirl, Venetia Burney, suggested the name Pluto, the god of the underworld. Tombaugh’s ...

Here's what to know about the short life of what was, for a single human lifetime, the solar system's smallest planet. Pluto was discovered in 1930 by Clyde Tombaugh, an American astronomer at the ...