Researchers first suggested the existence of a ninth planet in January. Despite its supposed massive size estimated to be 10 times that of the Earth, the extraterrestrial world may have evaded telescopes because of its extreme distance from the sun. According to calculations, a year on this planet is equivalent to 17,000 years on Earth.
Even with mounting interest in this object, NASA has said that the idea of a ninth planet lying in the far outer realm of the solar system is still theoretical. Astronomers, however, keep finding phenomena that can possibly be attributed to the existence of the so-called Planet Nine.
Now, researchers propose that the curious tilt of the sun could be attributed to this undiscovered world.
In a new study, California Institute of Technology planetary scientist and astrophysicist Elizabeth Bailey and colleagues suggested that the influence of Planet Nine may be responsible for the unusual tilt of the sun. The elusive planet may be adding wobble to the solar system, which gives the appearance that the sun is slightly tilted.
Bailey explained that because the elusive planet is massive and has an orbit that is tilted compared to those of the other planets, the solar system has been coaxed to slowly twist out of alignment.
All the other planets in the solar system orbit in their original plane. The sun also rotates on its own axis, but the spin appears tilted. It rotates at a six-degree tilt relative to the line perpendicular to the plane of the planets.
Scientists do not have a clear explanation for this, but the new study offers a new theory: a hypothetical massive object lying in the outer solar system may be interfering with the orbits of the other planets.
"But what's actually going on is that the Sun is staying put in its fixed reference frame and it's the planetary orbits that are being tilted by Planet Nine," explained theoretical astrophysicist Konstantin Batygin, also from Caltech.
"So Planet Nine has tilted the entire disk of the solar system by 6 degrees and because we live on that disc ... to us it looks like the Sun is tilted, but it's actually the other way around."
Researchers ran computer simulations that revealed that the tilt of the eight planets may be due to the gravitational influence of the yet to be discovered Planet Nine over the course of the 4.5 billion year lifetime of the solar system.
"Because we think Planet Nine has a significant inclination, if it exists, then that means it would tilt things," Bailey explained. "It's one puzzle piece that seems to fit together, and it really seems to be in support of the Planet Nine hypothesis."
The findings will be published in an upcoming issue of the Astrophysical Journal.