As researchers continue to map their orbits, they’re finding growing evidence that something massive—yet invisible—may be lurking in the cold, dark outskirts of our solar system.

It's possible for our solar system to capture a rogue planet and give it a home as it hurtles through the galaxy, according to a new study. In 2017, astronomers at the Pan-STARRS1 observatory were ...

An object eight times the mass of Jupiter may have swooped around the sun, coming superclose to Mars' present-day orbit before shoving four of the solar system's planets onto a different course.

A tiny object far beyond Pluto, newly discovered by the Subaru Telescope, could reshape our understanding of the early Solar System. Named 2023 KQ14, this rare “sednoid” follows an unusual ...