The head of NASA says maybe Pluto is a planet after all. He is wrong because Pluto is part of the rest of the solar system ...

It's been 20 years since Pluto lost its status as the ninth planet of the solar system, but we still can't seem to let it go.

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 ...

NASA chief Jared Isaacman’s call to restore Pluto’s planetary status has reignited a long-running scientific debate over ...

After nine years and a journey of 4.8 billion kilometres, NASA's New Horizons robotic probe awoke from hibernation on Saturday to begin an unprecedented mission to study the icy dwarf planet Pluto and ...

(Correction: An earlier version of this story misstated how far Pluto is from the sun. The correct number is 3.7 billion miles.) What was discovered in Flagstaff, Arizona, and killed off in Prague? If ...

The solar system consists of our star, the sun, and everything bound to it by gravity: the planets Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune, along with dwarf planets like ...

An image of Pluto taken by NASA's New Horizons spacecraft on July 13, 2015. The planet was first discovered by Clyde Tombaugh, who graduated from high school in rural Kansas and went on to earn his ...