Scientists have unveiled an enormous gas cloud just 300 light-years from the solar system that measures about full 40 moons ...

The morning of April 24 will give rise to a striking mini-planetary parade, as Mercury, Venus, Saturn, Neptune, and Earth's ...

If Planet Nine is found, it would be the first such discovery since Neptune in 1846 and would mark a monumental shift in our understanding of how the solar system formed and evolved.

Mike Brown is convinced that beyond Neptune, at the far reaches of our solar system, there's an unseen giant planet. "This is the 5th largest planet in our solar system, lurking out there ...