Learn how a possible ninth planet, the theoretical Planet X, could have acquired its wide orbit in the outer Solar System - a ...

A small team led by Sihao Cheng, Martin A. and Helen Chooljian Member in the Institute for Advanced Study's School of Natural ...

A new dwarf planet, discovered beyond Neptune and described as Pluto's 'cousin,' could void the hypothesis of a Planet X in ...

Today, it’s believed that Jupiter and Saturn, the largest planets, were the first to fully form, both within a few million ...

In the cold, dark outskirts of planetary systems far beyond the reach of the known planets, mysterious gas giants and ...

Our solar system’s origin story spans billions of years and involves clouds of gas, cosmic collisions, and planetary ...

Astronomers find evidence of a possible ninth planet beyond Neptune, reigniting the debate about the formation of the Solar ...

Astronomers have just discovered a new celestial body in our solar system that could challenge major space theory. 2017 OF201 ...

A new telescope project called the Next-Generation Very Large Array will revolutionize radio astronomy if it gets the funding ...

Our solar system may have a ninth planet after all, following the declassification of Pluto nearly two decades ago, researchers say.

Earth has four seasons, but do other planets in our solar system also have hot summer days and cold winter nights?

A team of astronomers believe they may have discovered a new dwarf planet—just like Pluto—on the edge of our solar system.