Jul 23, 2016 I Paul Seaburn

New Theory: Planet 9 Knocked Solar System Out of Alignment

Call it Planet 9 or Planet Nine. Call it Planet X. Don’t call it anything at all if you don’t believe it exists. Whatever you call it, Planet 9 is constantly attracting new speculation about its alleged existence, mysterious birth, possible location and affect on the rest of the planets in our solar system. The latest theory – developed by two different astronomers independently – proposes that Planet 9 knocked the other planets in the solar system 6 degrees out of whack in relation to the axis of the Sun. How could this have happened (and can we sue)?

Because we think Planet Nine has a significant inclination, if it exists, then that means it would tilt things. It’s one puzzle piece that seems to fit together, and it really seems to be in support of the Planet Nine hypothesis.

Elizabeth Bailey of the California Institute of Technology (Caltech) is one of the astronomers speculating on Planet 9’s influence on the misalignment of the solar system. What is this misalignment or 'tilt'? It’s been assumed that the eight planets orbit in the original plane they were in when they came into being. The sun’s axis should be perpendicular to this plane but it’s been measured to be 6-7 degrees off kilter. Some early theories blamed the tilt on gravitational influence by a passing rogue star. Bailey, who works with Planet 9 gurus Michael Brown and Konstantin Batygin, believes that the sun is OK but the rest of the planets were knocked out of line by Planet 9.


Interesting, but how did they manage to all stay in the same plane and not be randomly scattered? Bailey’s model is based on the idea that the shift happened early in the life of the solar system. With a drastically different orbital plane relative to the rest of the planets, the model shows that Planet 9 could have pulled Jupiter, Saturn, Uranus and Neptune out of line as a group with the little planets tagging along.

planet orbits sideview 570x314
Plane of planets (dwarf planet Pluto is out of line)

Working independently, Alessandro Morbidelli at Côte d’Azur Observatory in Nice, France, focused his model on mass and found that it had less influence on the other planets that orbital tilt. If the shift was caused by mass, Jupiter would have done it first, so he agrees with Bailey.

These theories provide a nice explanation for the off-kilterness of the Sun. Do they prove the existence of Planet 9? Not yet.

Paul Seaburn

Paul Seaburn is the editor at Mysterious Universe and its most prolific writer. He’s written for TV shows such as "The Tonight Show", "Politically Incorrect" and an award-winning children’s program. He's been published in “The New York Times" and "Huffington Post” and has co-authored numerous collections of trivia, puzzles and humor. His “What in the World!” podcast is a fun look at the latest weird and paranormal news, strange sports stories and odd trivia. Paul likes to add a bit of humor to each MU post he crafts. After all, the mysterious doesn't always have to be serious.

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