According to Dr. Grundy, Pluto is a planet. "I use the word 'planet' to refer to it, and most of the planetary science community does too," Grund ...

Feb. 18 marks the 95th anniversary of the discovery of our outermost planet-not-planet. Here's what to know about the short ...

Pluto will mark a birthday of sorts on March 23, 2178. No one is likely to be there to celebrate it, of course. Even if ...

For decades, Pluto was celebrated as the ninth planet of our solar system. However, in 2006, the International Astronomical Union (IAU) redefined what constitutes a planet, leading to Pluto’s ...

An curved arrow pointing right. Former planet Pluto may have been miscategorized yet again. A recent analysis of its atmosphere showed that it may be something we've never seen before — a comet ...

Pluto may not be a planet any more, but you still have a chance to see the distant dwarf planet at one of Michigan's ...

And today, over 12 years later, people still have strong opinions whenever you ask: Should Pluto be a planet again? - I'm not really sure that I have an opinion of whether or not Pluto should be a ...

In August 2006, the International Astronomical Union made the controversial, but correct, decision to demote Pluto from its status as the ninth planet in our Solar System. From that day forward ...