There may be another planet in the Solar System. This “ghost” planet that would be beyond Neptune it has never been directly observed, but its existence would serve to explain the anomalous orbits of several celestial objects at the edge of the Solar System. A few days ago research was published on arXiv with new evidence in favor of the existence of this “planet nine”: «We have found further evidence indicating the existence of the planet. The new work represents the strongest statistical evidence that Planet Nine is really out there» said astronomer Konstantin Bogytin.
The first studies on planet nine date back to the end of the nineteenth century, and research continued in the 2000s. Last year, two Japanese astrophysicists published a study in which they analyzed the data collected on celestial objects in the Kuiper beltwhose anomalous orbit would find an explanation by hypothesizing the existence of a ninth planet.
Decisive information for or against the existence of planet nine is expected fromVera C. Rubin Observatoryin Chile, currently under construction, which once completed will contain instruments to “scan” the celestial vault and provide a detailed map of the sky.
What we know about planet nine
Called planet nine (ninth after Pluto’s downgrading in 2006), or even ghost planet and planet (x intended as an unknown, not as the Roman numeral), this celestial body is described by astronomers as resembling the Earth. It should be about three times larger of it, however it is a lot unlikely to host life, at least as we know it, because the temperatures in the Kuiper belt are too low: to have a comparison we can consider the fact that the asteroids in this belt have a temperature of -220 °C. The planet is also called trans-Neptunian (Tno), to indicate that it is beyond Neptune, on the edge of the Solar System, and would revolve around the Sun precisely in an orbit near Neptune.
Why its existence was hypothesized
To this day, the theory exists that there is a “hidden” planet in the Kuiper belt it is not universally accepted. The existence of planet nine has been hypothesized because would explain the trajectories of some trans-Neptunian objects observed at the edge of the Solar System, at a distance from the Sun approximately 250 times greater than that of the Earth: these have unusual orbits, a possible indication of an unknown gravitational field influencing their movements.
Compared to past studies, the research published on arXiv takes into consideration celestial objects whose anomalous movements interact with Neptune’s orbit, and for this reason they are even more difficult to understand. The results of the study reveal that the orbital architecture of this group of objects can be explained if the presence of another planet is hypothesized, which constitutes, according to the group of astronomers, strong evidence in support of the existence of planet nine. The movements of these trans-Neptunian objects are caused by a number of factors: they feel, among others, the influence of Neptune and the Milky Way, but according to researchers the best explanation for their behaviors is that of the model that includes the presence of planet nine.
