On August 24, 2006, our solar system lost a planet. It wasn't by cataclysmic destruction, but rather by the vote of the International Astronomical Union, which declared that Pluto, considered the ...

Pluto hasn't been a planet for almost 20 years. In the early 2000s, scientists discovered several objects of a similar size to Pluto. So, during the summer of 2006, members of the International ...

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 ...

In 2006, updated research led to Pluto being controversially demoted to dwarf planet status by the International Astronomical Union. The reasoning was that Pluto's location in the far-flung ...

Astronomers have identified a small but significant possibility that a Neptune-sized planet is quietly orbiting within the ...

Scientists may have discovered a dwarf planet far beyond Neptune — an unearthing that may disprove a longstanding theory about the possibility of a giant ninth planet. The dwarf planet's existence ...

Might the solar system harbor not just one, but two unknown planets? A fresh study of the Kuiper Belt’s structure has revived ...

A newly discovered warp in the outer Solar System may have been created by a small, rocky world, much closer to the Sun than ...

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 ...

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 ...

NASA's New Horizons spacecraft captured this high-resolution enhanced color view of Pluto that is inserted beneath the Short Wave logo. The image combines blue, red and infrared images taken by the ...