The relative quantities of volatile gases like methane and ethane can reveal key details about distant Kuiper Belt objects.

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

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 ...

The top finisher is a shocker Why Pluto isn't part of any planet parades For those people still scratching their heads, trying to figure out why the solar system has fewer planets now than it did ...