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 ...

Astronomers have discovered a new Earth-sized planet located 146 light-years from our solar system. The planet, named HD ...

When you buy through links on our articles, Future and its syndication partners may earn a commission. A composite image comparing the relative sizes of our solar system's known dwarf planets, ...

Our solar system today has eight planets. Till a few years back, Pluto was our ninth planet, until it was demoted to a dwarf planet. But some studies suggest that the ancient solar system once still ...

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 dubbed ...

LONDON — 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 ...

Planet Y is the latest in a series of hypothetical solar system planets that scientists have proposed in recent years, all with slightly different characteristics but collectively believed to be ...

(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 ...