Two decades ago, the International Astronomical Union—which defines and names celestial bodies—redefined the criteria for ...

Pluto was downgraded from a planet to a dwarf planet in 2006 by the International Astronomical Union. The main reason for Pluto's demotion is that it's not able to "clear its orbit of debris." Other ...

Although Seeing in the Dark doesn't directly discuss Pluto, it does celebrate the joy of observing planets. Viewers who watch the show may wonder what happened to Pluto in 2006 and whether any of the ...

Not much to name in our current view of Pluto (left). That will all change during the July flyby when New Horizons will image features down to 1 mile (1.6 km) across. Credit: NASA Here's your chance ...

Add Yahoo as a preferred source to see more of our stories on Google. Guests visting the Lowell Observatory in Flagstaff, Arizona during the I Heart Pluto Festival gaze at celestial objects from the ...