There could be a ninth planet in our solar system that's lying in wait to be discovered - and no, it's not Pluto. Our solar ...

Mercury has long baffled astronomers because it defies much of what we know about planet formation. A new space mission ...

The giant planets weren't always where we find them today. Jupiter, Saturn, Uranus and Neptune formed in a more compact configuration and later underwent a violent reshuffling that scattered them to ...

By tracking tiny stellar wobbles, astronomers have detected planets forming around young stars for the first time.

CAPE CANAVERAL, Fla. — Astronomers have discovered a rare solar system in the Milky Way that boasts six planets orbiting in perfect rhythm like a cosmic orchestra, untouched by outside forces since ...

The newly identified cluster of Kuiper Belt objects lies about 4 billion miles from the Sun, offering fresh clues about how ...

Jupiter is the largest planet in the solar system, known for its massive size, strong gravity, powerful storms and many moons ...

Astronomers are uncovering distant worlds beyond our solar system using ingenious indirect methods like observing stellar ...

found outside our solar system to 100, and scientists are now seeing a pattern in the orbits, giving clues to how they form. The new planet, which has a mass about that of Jupiter, circles its star ...

This transcript was prepared by a transcription service. This version may not be in its final form and may be updated. Danny Lewis: Almost 800 million miles away from Earth, the moon Enceladus orbits ...

The International Astronomical Union (IAU) defines a planet as a celestial body orbiting the Sun, possessing sufficient mass for a nearly spherical shape, and having cleared its orbital neighborhood ...