Astronomers have found a compact solar system whose planets line up in a way that, according to current models, should not be ...

Scientists say a nearby red dwarf star hosts a planetary lineup that looks like a mirror image of our own solar system, with ...

By Will Dunham WASHINGTON, Feb 14 (Reuters) - Astronomers have observed a planetary system that challenges current planet formation theories, with a rocky planet that formed beyond the orbits of its ...

Add Yahoo as a preferred source to see more of our stories on Google. An illustration showing Planet Nine, a hypothetical, undiscovered planet in our solar system. New research now suggests the ...

Scientists have been trying to find a hypothetical Planet 9 that may exist outside our known solar system based on the unusual orbits of certain dwarf planets. But those orbits might not require a ...

The orbits of the planets around the Sun have been the source for many a scientific debate. Their current orbital properties are well understood but the planetary orbits have evolved and changed since ...

A new discovery suggests the possibility of an exomoon with an unprecedentedly large mass, thousands of times larger than any moon in our Solar System.

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 ...

The Sun is an incandescent but benevolent dictator. For billions of years, it’s kept our star system well organized through the influence of its powerful gravity. All the planets revolve around it on ...

Meet the surprising, oddball worlds moving around our solar system. From meteorites that impact Earth, to a moon that orbits backwards, to an imposter lurking in the asteroid belt, a variety of ...

Researchers estimate that the planet has about a 50% chance of being in its star's Hoble zone.