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 planets in order from the Sun are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. If you include the ...

Close stellar encounters could change the structure of our planetary system, potentially dooming Earth or other worlds to ...

Scientists may have discovered a dwarf planet far beyond Neptune — an unearthing that may disprove a longstanding theory ...

An initial analysis suggests the object could be a young, cold planet with a temperature near 120 degrees Fahrenheit, NASA ...