The status of Pluto not withstanding, our solar system has 8 planets, but one astronomer believes we used to have a ninth ...

The solar system lost its ninth planet back when Pluto was demoted to a dwarf planet, but research might indicate that there ...

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 ...

If you don’t count Pluto, and the scientific community doesn’t, there are eight planets in this solar system of ours. We know of only one to have life, and we suspect another one might have, at some ...

(CNN) — The search for an unknown planet in our solar system has inspired astronomers for more than a century. Now, a recent study suggests a potential new candidate, which the paper’s authors have ...