Our solar system may have a ninth planet after all, following the declassification of Pluto nearly two decades ago, ...

Researchers say they found a curious dot on infrared images taken 23 years apart that seems to be moving in a manner consistent with a large, distant planet.

Astronomers may have found a candidate for Planet Nine. This planet is beyond Neptune. The finding could be the first ...

Earth has four seasons, but do other planets in our solar system also have hot summer days and cold winter nights?

A new look through decades-old data has unveiled some of the most compelling evidence yet of a hidden ninth planet in the far ...

Discovered in 1930, Pluto was long considered our Solar System's ninth planet, but was unseated in 2006 after the discovery ...

The solar system consists of our star, the sun, and everything bound to it by gravity: the planets Mercury, Venus, Earth, ...

Warmer climates than Earth’s could accelerate life’s development, potentially increasing the number of planets with more ...

sitting in the Kuiper Belt - a region in our solar system beyond Neptune filled with icy objects, comets, and dwarf planets like Pluto. Since this hidden planet may be so far away, the new study ...