Pluto once held its place proudly as the ninth planet in our solar system,a distant, icy world on the edge of the cosmic frontier. But in 2006, everything changed. This in-depth explainer unpacks the ...

Pluto was long considered our ninth planet, but the International Astronomical Union reclassified Pluto as a dwarf planet in ...

How long does it take Pluto to orbit the sun? Learn more about how this planet makes one lap around our Solar System.

How many dwarf planets are there in our solar system? The recent discovery of 2017 OF201 makes the tally anywhere between ...

Sedna will make its closest approach to the Sun in 2076, giving us a rare opportunity to visit the planetoid before it drifts ...

OF201, the object belongs to the same all-star family as Pluto: dwarf planets. Its diameter, roughly 435 miles (700 km), is half Pluto’s, ...

In the outer reaches of our solar system, far beyond the orbit of Pluto, lies Sedna, one of the most mysterious objects ever ...

For the dwarf planet candidate, one trip around the sun takes over 24,000 years. Its orbit challenges a proposed path for a hypothetical Planet Nine.