A theoretical, distant and undiscovered planet in the solar system may be why the sun is tilted, according to a new study released this week by Caltech scientists.
It's called Planet Nine, NBC News reported, and it is said to be lurking deep in the Milky Way, tilting the planets in our solar system by as much as six degrees — or so the calculations say.
"Because Planet Nine is so massive and has an orbit tilted compared to the other planets, the solar system has no choice but to slowly twist out of alignment," said Elizabeth Bailey, lead author of the study announcing the discovery.
Planet Nine remains a mystery. It was proposed through computer and mathematical modeling, but one has actually seen it yet, far beyond Pluto, which used to be thought of as the ninth planet.