A distant, icy body circling the Sun far beyond Neptune has handed astronomers a fresh puzzle. Designated 2023 KQ14 and nicknamed Ammonite, the trans-Neptunian object follows a Sedna-like orbit with a ...

Two faint objects hiding in archival infrared sky maps now sit at the center of a growing scientific argument about whether a massive, unseen planet orbits far beyond Neptune. Researchers mining data ...

See more of our trusted coverage when you search. Prefer Newsweek on Google to see more of our trusted coverage when you search. A distant exoplanet that shouldn't be there anymore has continued to ...

In the 1820s, French astronomer Alexis Bouvard speculated that Uranus’ irregular orbit was being influenced by an eighth planet in our solar system, leading to the discovery of Neptune. In 2016, ...

Researchers at the California Institute of Technology (Caltech) have found new evidence that further suggests there is a ninth planet in our solar system. Nicknamed "Planet Nine," researchers said ...

In January 2015, a team of astronomers made a shocking discovery that would alter our understanding of the Solar System. Deep within the confines of the outer Solar System, a giant ninth planet may be ...

Astronomers know very little about the far outer Solar System — beyond Neptune, Pluto, and the far-flung Kuiper belt. For the past seven years, some scientists have observed certain gravitational ...