Scientists studying the interstellar object ‘Oumuamua have proposed that it may be a fragment from a Pluto-like planet beyond ...

Earth has a newly-discovered neighbor in the solar system. But the heavenly body – possibly a dwarf planet à la Pluto – isn't a frequent visitor. Located beyond Neptune, its extreme orbit ...

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 ...

For decades, Pluto was our solar system's ninth planet. This video explains the scientific journey that led to its ...

A recent research paper suggests that a planet may exist far beyond Neptune — less than 20 years after the previous ninth planet, Pluto, was demoted. That research paper, accepted last month for ...

LONDON — The search for an unknown planet in our solar system has inspired astronomers for more than a century. Now, a recent study suggests a potential new candidate, which the paper's authors have ...

(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 ...

WASHINGTON (AP) — There’s a chaotic dance going on at the far end of our solar system, involving Pluto and five of its closest friends, a new study finds. Hubble Space Telescope images of Pluto, its ...

On July 14, 2015, NASA's New Horizons spacecraft arrived at Pluto for the first time. The craft flew within 7,700 miles of the planet and is sending back reams of data and the highest resolution ...

Aug. 15, 2006 — -- When Clyde Tombaugh discovered Pluto in 1930, he made a mess of the solar system. Pluto was too small, too distant, and of the wrong makeup to qualify as a planet, many ...

When I was a kid, there were nine planets. Now we know of thousands! But that includes exoplanets, alien worlds that orbit alien suns. Only eight planets call our solar system home. Or there might ...