Dwarf planet 2023 KQ14, Ammonite, has a stable orbit that challenges the hypothesis of the mysterious Planet Nine.

For years, astronomers have been excited about the idea that some planets beyond our solar system might be covered by vast, ...

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. When ...

The comet, named 3I/ATLAS, is only the third confirmed interstellar object ever seen in our solar system. That means it came ...

The official number of exoplanets—planets outside our solar system—tracked by NASA has reached 6,000. Confirmed planets are ...