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 ...

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." ...

Pluto may have lost its status as a full-fledged planet in 2006, but that doesn't mean it's a joke of a world this April Fools' Day and the folks behind Pluto TV want to make that clear.

For one reason or another, some people are still upset about Pluto's demotion from planet to dwarf planet. This demotion, by the way, occurred all the way back in 2006. So, what does famed ...

Viewed in this longer context, the previously modern idea of having nine planets, which came about in the 1960s and lasted only until 2006, was a blip on the screen. And if you are still a Pluto ...

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 ...

An curved arrow pointing right. NASA's New Horizons spacecraft took us to Pluto for the first time in July 2015. Scientists are astonished by the incredible features they've observed on the dwarf ...

Sad face emoji for Pluto. When I was a boy reading books about the Solar System, there was Pluto at the edge of the double-page spread in the middle of the book, the furthest planet from the sun ...

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 ...