All of our solar system’s planets are lining up in the night sky at once this week. This extraordinary celestial event will see the sky scattered with seven visible planets in what is known as a great ...

A newly studied solar system breaks the usual planet pattern, raising fresh questions about how rocky and gas planets form.

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 ...

Stars passing close to the sun could cause planets to collide, including with Earth, or even be ejected as rogue planets, new simulations show. By Katherine Kornei If our species manages to hang on ...