Planet 9 may be here

There are eight known planets in the solar system (since then Pluto He was kicked out of the club), but for a while there was evidence that there might be another. A hypothetical planet 9 lurks on the outskirts of our solar system. So far, this scientist has escaped discovery, but a new study indicates where it should be.

The proof of the existence of planet 9 comes from its attraction to other bodies. If a planet is present, its gravity will affect the orbits of other planets. So if something seems to be working on a planet, you just need to do some math to find the source. this is the way Neptune It was discovered, when John Koch Adams and Urban Le Verrier independently noticed it Uranus It appears to be taken from an invisible planet.

In the case of planet 9, we have no gravitational influence on a planet. What we are seeing is a strange collection of small icy bodies in the Outer Solar System known as the Kuiper Belt Bodies (KBOs). If there was no planet outside the Kuiper Belt, you would expect the orbits of Kuiper Belt objects to be randomly oriented in the orbital plane of the Solar System. But instead, we see a lot of KBO orbitals clustered in the same direction. This is probably due to chance, but it is unlikely.

Probable orbit of the ninth planet. Credit: CalTech / R. Hurt (IAPC)

In 2016, the authors examined the statistical distribution of Kuiper Belt objects and concluded that the agglomeration was caused by an undetected exoplanet. According to their calculations, this world has a mass of 5 planets and it is about 10 times farther from the Sun than Neptune. The newspaper even calculated a large area of ​​the sky where the planet could be located. But the research did not yield anything. This has led some to conclude that the planet does not exist. Orbital eccentricities do not prove the existence of a planet. Just ask the planet Vulcan. Others have gone so far as to say that planet 9 exists, but that we cannot see it because it is primitive. Black hole.

This new study re-examines the original work in light of some of the criticism it has received. A big criticism is that the outer bodies of the solar system are hard to find, so we are looking for them in the right place. The clustering effect we see could be due to biased data. Taking into account observation bias, the authors found that clustering was still statistically unusual. There’s only a 0.4% chance that it’s just a coincidence. When they recalculated the probable orbit of Planet 9, they were able to better determine where to look.

An interesting aspect of the study is that the newly calculated orbit brings Planet 9 closer to the Sun than originally thought. It’s weird, because if he was closer, we should have found him already. The authors argue that observations so far have ruled out the closest options for Planet 9, helping to further refine its potential location. If the planet exists, it should be detectable by the Vera Rubin Observatory in the near future.

This study is inconclusive, and many astronomers still argue that planet 9 does not exist. But this study shows that we won’t have to discuss it any longer. Either it will be discovered soon, or observations will rule out it as an explanation for the influence of the KBO group.

Reference: “Planet Nine’s Orbit” by Michael E. Brown and Konstantin Batygin, August 22, 2021, Astrophysics> Astrophysics of the Earth and the planets.
arXiv: 2108.09868

Originally published in Universe Today.