Something Big Is Warping Our Outer Solar System

schwit1 quotes Futurity:
The plane of our solar system is warped in the outer reaches of the Kuiper Belt, suggesting the presence of an unknown Mars-to-Earth-mass planetary object far beyond Pluto -- but much closer than Planet Nine. An unknown, unseen "planetary mass object" may lurk in the outer reaches of our solar system, according to new research on the orbits of minor planets.

The object would be different from -- and much closer than -- the so-called Planet Nine, a planet whose existence has yet to be confirmed... "The most likely explanation for our results is that there is some unseen mass," says Kat Volk, a postdoctoral fellow at the University of Arizona's Lunar and Planetary Laboratory and lead author of the study in the Astronomical Journal. "According to our calculations, something as massive as Mars would be needed to cause the warp that we measured."