Astronomers have uncovered a massive new trans-Neptunian object, 2017 OF201, lurking at the edge of our solar system. With an ...

The solar system lost its ninth planet back when Pluto was demoted to a dwarf planet, but research might indicate that there ...

Astronomers have picked up evidence of an Earth-sized world, distinct from the previously hypothesised Planet Nine and Planet ...

As our understanding of the outer solar system has grown, we’re facing new questions. And it’s renewing talks about planets past Neptune. And not Pluto, Eris, Makemake, or the other ...

NASA's Hubble Space Telescope has returned a batch of incredible close-up photos of the planets Jupiter, Saturn, Uranus and Neptune.

Outer solar system scientists have prepared three mission concept studies considering what flagship missions to Enceladus, Neptune and Triton, and Pluto could do.

Among the solar system’s more intriguing mysteries is whether a large, icy planet lives in the outer regions of our cosmic neighborhood, well beyond the orbit of Neptune. This hypothetical world ...

Although a Planet X may exist, none has been found. Still, intense interest in the outer solar system has paid off handsomely.

Today, let's talk about those massive planets in the universe. Have you ever wondered why giant planets rotate so quickly?