As astronomers look to confirm the existence of a ninth planet in the outer edges of our Solar System, one study suggests evidence for the distant body could be found right at the centre, in the tilt of our Sun.
Planet Nine was predicted by Konstantin Batygin and Mike Brown from Caltech at the beginning of 2016.
The hypothetical planet is thought to be about ten times the mass of Earth with an orbit that takes it 20 times farther from the Sun on average than Neptune’s.
The existence of the planet has been strengthened by various studies over the years, but there's one that suggests it could be responsible for adding a wobble to the Solar System that causes the Sun to appear tilted.
More on our Solar System
Wait, our Solar System's tilted?
The planets in the Solar System orbit on a flat plane that rotates at a 6° tilt with respect to the Sun, which makes it appear that our host star sits at an angle.
However, no conclusive answer as to why this happens has ever been found.
From Batygin and Brown’s calculations, we know that Planet Nine appears to orbit about 30° off compared to the orbital plane of the other planets, and that its orbit has an influence on objects in the Kuiper Belt on the edge of the Solar System.
The study suggests that, while the other eight planets in the Solar System should exist on a flat plane with respect to the Sun, their orbits are being tilted by the existence of a ninth planet.
According to Brown, the calculated size and distance of Planet Nine would fit the 6° tilt of the orbital plane.
"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," says Elizabeth Bailey, lead author of the study.
Although it is not yet known how such a planet would develop such an unusual orbit, one theory is that Planet Nine could have been pushed to the outer edges of the Solar System by Jupiter, or else pulled away from the centre by other bodies in the past.
Read the full paper in the Astronomical Journal
