Is there a massive undiscovered planet on the outer reaches of the solar system? The idea has been around since before the ...

The celestial body's unusual orbit “implies that something extraordinary occurred" in the early days of the solar system—and ...

A newly discovered dwarf planet called 'Ammonite' (2023 KQ14) has been spotted in the outer solar system, and it could be ...

Evidence that rocky planets beyond Jupiter formed as rapidly, and at the same time, as the inner planets could transform our ...

Scientists have been able to recreate the extreme conditions found on icy moons in deep space—and revealed the unstable ...

Aliens are visiting our solar system. Not little green men, sadly, but natural alien objects—cosmic bodies such as comets and ...

From quasi-moons to asteroids with rings, the Solar System is beaming with weird and exotic objects that tell the story of how it came to be billions of years ago. Arrokoth As an ancient ...

The category "dwarf planet" was created in 2006 to make room for the many large bodies being discovered on the outer reaches of the solar system. Here's a tour of the five currently recognized ...

Our solar system was formed from such a disk about five billion years ago. NASA’s Spitzer telescope has found dozens of disk-sporting brown dwarfs so far, several of which show the initial ...

The most distant solar system object known, informally named “FarFarOut,” appears as a faint dot against background stars in this telescopic image. Further studies of FarFarOut could reveal ...