Until 2015, Pluto, the former ninth planet of the classical solar system, was largely a mystery—a tiny speck 3.6 billion miles from the sun. When NASA's New Horizons spacecraft arrived at the ...

For the better part of a century, we believed there were nine planets in our solar system, with Pluto being the farthest from the sun. Since the discovery of more Pluto-sized dwarf planets, that ...

Pluto is so far away from Earth that everything we know about it can be written down on a couple of 3 x 5 inch index cards. But Pluto will come into clearer focus in a few years' time, though, as NASA ...

Scientists announced the discovery of a new moon around Pluto today (July 11), bringing the dwarf planet's number of known satellites to five. The newfound Pluto moon was spotted by researchers using ...