A rare discovery beyond Neptune is forcing scientists to rethink early solar system dynamics and the forces that shaped ...

Astronomers are closing in on one of the most tantalizing possibilities in planetary science, evidence that a previously unknown world may be lurking in the outer reaches of the solar system. The ...

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 ...

Our Sun’s outer atmosphere, the corona, is millions of degrees hotter than it should be, and no one knows why.

In humanity’s millennia of staring at the stars and decades of launching probes to explore our universe, only two spacecraft carrying working instruments have ever managed to escape the bubble of ...