Sun's tilt attributed to influence of unseen Planet Nine
Planet Nine, the enigmatic body supposedly loitering somewhere in the furthest reaches of our solar system, has had one more set of observations attributed to it in what Caltech scientists consider the most definitive proof of its existence to date. In this latest work, the researchers claim that the previously unexplained tilt of the Sun itself is a direct result of the gravitational influence of this yet-to-be-observed world and further verification of its presence.
Much speculation has been made about Planet Nine since Caltech scientists first espoused the possibility of its existence, from where it may have come from to theories on its construction. Now large perturbations in trans-Neptunian/Kuiper belt objects announced earlier this year has led to this latest research explaining the strange tilt of the Sun in respect to the orbital plane of the planets.
According to the Caltech researchers, the angular momentum of Planet Nine is exerting an influence on the Solar System because of its position at about a 30 degree angle to the orbital plane and its enormous mass of around 10 times that of the Earth. Spinning about the Solar System at a distance of some 700 AU from the Sun, Planet Nine exerts a small, but influential, sway on the overall spin of the Solar System.
By tugging at the other planets, it is theorized that Planet Nine pulls the entire spinning disk of bodies slightly out of their flat plane, to some six degrees away from horizontal in relation to the Sun.
"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, graduate student at Caltech and lead author of the study.
The observed influence on the orbit of a great proportion of objects in the Kuiper Belt is how Caltech scientists first came to suspect a planet existed somewhere in the outer edges of the Solar System, but the tilt of the Sun that had perplexed astronomers for decades was the real clincher. Because, in a standard, spinning solar system, the angular momentum of the planets would ordinarily be expected to form a flat plane more or less horizontal in relation to the star around which they are orbiting, such a large tilt to our system is almost certainly due to the effect of an external massive body.
"It continues to amaze us; every time we look carefully we continue to find that Planet Nine explains something about the Solar System that had long been a mystery," says Konstantin Batygin, assistant professor of planetary science at Caltech.
The results of the research will be presented at the 48th meeting of the Division for Planetary Sciences (DPS) and 11th European Planetary Science Congress (EPSC) in Pasadena, California, 16 - 21 October.
The video shown below is a Q&A with Caltech astronomers discussing their theory.