New research may have solved a "deep-rooted mystery" about our solar system and lent credence to the theory that there's a ninth planet chilling beyond Pluto. (Sorry, buddy.) Researchers at Caltech, including Konstantin Batygin and Mike "Pluto Killer" Brown (who first floated the "Planet Nine" theory), say evidence of the massive body has been right under our noses—or actually above our heads—all this time: The planet may cause the sun to appear tilted. How? Well, the orbits of all other planets in our solar system are mostly flat, yet the zone in which they orbit the sun is tilted about six degrees off the sun's equator, per a press release. A massive hidden planet with an orbit set 30 degrees off the other planets' orbits would explain why that is.
Such a planet would give the solar system "no choice but to slowly twist," study author Elizabeth Bailey says, and calculations apparently check out, per the Guardian. There are other possibilities—that the planets were created this way or the sun's core influenced the orbits early on—but "Planet Nine is the first thing that has been proposed to tilt the solar system that doesn't depend on early conditions, so if we find Planet Nine, we will be able to see if it's the only thing responsible," Bailey tells Space.com. Separate research from the University of Arizona notes a massive planet would also explain odd orbits in the Kuiper Belt, the region beyond Neptune's orbit. If there isn't a ninth planet, "it has to be that there was one there yesterday and [it] disappeared," Brown says. (Astronomers recently made a "jackpot" discovery.)