A new study from researchers at the California Institute of Technology (Caltech) suggests that Planet 9, the huge and so far unseen planet said to be lurking in the far reaches of the solar system, might be causing our group of planets to wobble a little and giving an impression that the sun is slightly tilted.
Elizabeth Bailey, lead author of the new study, points out the planets in our solar system orbit in a relatively flat plane with the sun.
But she says that plane rotates at a six-degree angle, making the sun look like its actually tilted.
She and her colleagues assert in their study that the enigmatic Planet Nine is so massive and has such a lopsided orbit compared to the other planets, that our solar system can’t help but slowly twist itself out of alignment.
Astronomers have long been puzzled by this tilt of the orbital plane, especially because of how the planets are said to have been formed.
The most popular theory among scientists is the ‘protoplanet hypothesis’ (pdf), which suggests the planets were eventually formed from a rotating cloud of gas and dust left over from the creation of the sun. Over time, gravity caused the cloud particles to gather and accumulate into objects such as planets.
“It’s such a deep-rooted mystery and so difficult to explain that people just don’t talk about it,” says Mike Brown, a Professor of Planetary Astronomy at Caltech in a press release.
Brown, along with his Caltech colleague Konstantin Batygin, caused quite a stir in the scientific community back in January after they uncovered evidence of the mysterious Planet 9.
The evidence of Planet 9 gathered by Brown and Batygin suggest that it has a mass that’s about 10 times more than Earth and 5,000 times that of Pluto.
It is also thought to orbit the sun from a distance of nearly 20 times farther than Neptune, whose average distance to the sun is about 4.5 billion kilometers.
Brown says that with the theorized size and distance of the giant mystery planet, the six degree tilt in the orbital plane fits perfectly, mathematically.
“It continues to amaze us; every time we look carefully we continue to find that Planet 9 explains something about the solar system that had long been a mystery,” says Batygin.
Astronomers continue to scan the skies in hopes of actually spotting and imaging Planet 9.
Video: Planet Nine Tilts the Sun! Q&A with Caltech Astronomers (Caltech)