The boundary of a solar system is not defined by planets, but by gravity. Beyond Pluto and the Kuiper Belt lies the Oort ...

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

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 ...

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 ...

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 ...

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 ...

CAPE CANAVERAL, Fla. — Astronomers have discovered a rare in-sync solar system with six planets moving like a grand cosmic orchestra, untouched by outside forces since their birth billions of years ...

Astronomers have been searching for evidence that Planet Nine exists for years Becca Longmire is a digital news writer-reporter at PEOPLE. She has been working at PEOPLE since 2024. Her work has ...

Astronomers gazing upon a star system not too far from Earth were recently treated to a marvelous discovery: a group of six planets moving around a sun-like star in a seemingly perfect cosmic dance ...

(WHTM) – When you look into the night sky, you’ll see planes flying by, stars twinkling, and sometimes you’ll see planets. Mercury has 88 days in a year and is a terrestrial planet. The size of ...

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

(CNN) – Astronomers have discovered a rare family of six planets about 100 light years from Earth. The exo-planets are larger than the Earth but smaller than Neptune. The planets are in a ...