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 ...

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

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 ...

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 have narrowed down on the possible location in the Solar System where the elusive planet nine may be hiding, an advance that could shed more light on the evolution of our abode in the ...

For years, astronomers have been searching for a ninth planet in our solar system (after giving Pluto the old heave-ho and demoting it to a dwarf planet) and now researchers say they've found a ...

We've just learned of a new neighbour — scientists say they have confirmed the discovery of a rocky planet outside our solar system that is closer to Earth than any ever found before. "Most of the ...

This artist’s concept depicts one of the solar system’s inner planets slamming into Earth after being nudged on a collision course by a passing star. Such a world-shattering cataclysm is extremely ...

PARIS: It's an evocative idea that has long bedevilled scientists: a huge and mysterious planet is lurking in the darkness at the edge of our solar system, evading all our efforts to spot it.Some ...