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 ...

According to the IAU, a planet must: Orbit the sun (Pluto does this). Be spherical in shape (Pluto is round due to its gravity). Clear its orbit of other debris (Pluto fails this). Pluto shares ...

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." ...

Clyde Tombaugh discovered Pluto in 1930 at Lowell Observatory in Flagstaff. Here's how Pluto won - and lost - its planetary status.

It must be massive enough for its gravity to pull it into a nearly ... Unlike the eight recognized planets, Pluto shares its orbit with many other objects in the Kuiper Belt, meaning it has ...

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." Kevin Schindler, Lowell Observatory's Public ...

It takes Pluto slightly over 248 Earth years to orbit the sun, which means that on March 23, 2178, one Plutonian year will have elapsed since the dwarf planet was first spotted, on Feb.

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 ...

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 ...