The giant planets weren't always where we find them today. Jupiter, Saturn, Uranus and Neptune formed in a more compact ...

A vast ring of rocky leftovers between Mars and Jupiter, the asteroid belt preserves clues to how the planets — and Earth ...

There have been questions about a mysterious ninth planet in our solar system for nearly a decade. Pluto was unseated as number nine in 2006. Now, a group of international researchers say they may ...

The first exoplanet ever discovered in 1995 was what we now call a "hot Jupiter," a planet as massive as Jupiter with an ...

LONDON — The search for an unknown planet in our solar system has inspired astronomers for more than a century. Now, a recent study suggests a potential new candidate, which the paper's authors have ...

When it comes to planets in our Solar System's habitable zone, one world is too close to the Sun, another is too far and ...

New high-contrast images from SPHERE show a stunning variety of debris disks shaped by collisions of tiny planet-building ...

Discover which planet is the fastest in the solar system. Learn why Mercury moves at 47 km/s, has the shortest year, and ...

Jupiter is already the biggest planet by far in our solar system, but new research suggests it was somehow once even larger than it is now. Twice as large, in fact. To put that into context, those ...

This is the strongest evidence yet of a rocky planet beyond our solar system with an atmosphere. Astronomers using the James ...

Researchers using NASA's James Webb Space Telescope have detected the strongest evidence yet for an atmosphere on a rocky ...