A newly discovered warp in the outer Solar System may have been created by a small, rocky world, much closer to the Sun than ...

A new study has proposed the existence of Planet Y, an alternative Planet Nine candidate that is smaller and closer to Earth ...

Now the idea can be extended to the orbit of all the planets, says Elizabeth Bailey, also at Caltech, who did the work together with Brown and Batygin. “Because we think Planet Nine has a significant ...