Scientists think they found evidence of a hidden planet beyond Neptune and they are calling it Planet Y
A planet more massive than Mercury could be lurking beyond the orbit of Pluto.
A planet more massive than Mercury could be lurking beyond the orbit of Pluto.
A 700-kilometer-wide object orbits farther than almost anything we've ever seen.
Astronomers have hunted for this planet since 2016. Could one more year of searching finally solve the mystery?
Hot moons could be the answer to finding the mysterious ninth planet.
An icy disk of smaller objects might be a better explanation.
It's more than 100 times farther away than Earth is from the sun.
An elusive planet ten times more massive than Earth may be lurking in the outer fringes of the solar system.
A ninth planet 10 times bigger than Earth might be lurking far away within the solar system.
Research narrowed down Planet Nine's orbit and confirmed there indeed seems to be a massive planet in the far reaches ...