For decades, our solar system was thought to have nine planets, with Pluto considered the smallest and farthest. But in 2006, Pluto was officially reclassified as a dwarf planet by the International ...

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 was reclassified as a dwarf planet in 2006. Our solar system may have a ninth planet after all, researchers say. The possibility that an additional planet may be hidden far into the solar system ...

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 ...

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 ...

Some experts believe that the solar system's hypothetical ninth planet could be just a few years away from being discovered. If this is the case, how long would it take for humans to send probes to ...

In an exciting breakthrough in planetary science, a recent study has increased the likelihood of Planet Nine’s existence by up to 40%. This planet, also referred to as Planet X, has remained an ...

A possible new dwarf planet has been discovered at the edge of our solar system, so far-flung that it takes around 25,000 years to complete one orbit around the sun. The object, known as 2017 OF201, ...