Planet X: here we are, maybe
Some people on the web has already dubbed Planet X, others talk about Nibiru, the planet which according Zecharia Sitchin passes every 3,600 years in the solar system approaching the Earth and then push behind the Sun, but astronomers Michael Brown and Konstantin Batygin, of the California Institute of Technology, who have officially announced the discovery on January issue of Astronomical Journal, until now not a result of direct observation but the calculations performed on the orbits of dwarf planets and other smaller objects that exist in the Kuiper belt, at the edges of the solar system, have preferred to just call it Planet Nine.
A name that indicates how the new member of the solar system is the candidate to take the place (lost in 2006 by Pluto) as the ninth “regular” planet and that it could support this role there seems no doubt, seen that based on its estimated mass it should have a diameter of two to four times that of the Earth, thus being the fifth largest planet in our solar system after the gas giants Jupiter, Saturn, Uranus and Neptune.
Difficult to say now whether this “disturbing giant”, as the scientists defined it, is destined, as assumed, for Nibiru, by Sitchin, to come closer to the Earth or other planets to the point of disrupting somehow the equilibrium of the solar system. At the moment it would be at a distance from the Sun about 20 times greater than that of Neptune, i.e. 600 astronomical units (the average distance Sun-Earth), but the perihelion is estimated at about 200 astronomical units.
Animation of the Solar System with the Planet Nine - Source: NASA
What is doing a planet so far away? Perhaps it was captured from a passing star when the solar system was forming (as it would have happened to Sedna, a dwarf planet trans Neptunian able to roam up to 975 astronomical distances and then stares up to 76 astronomical units) or maybe it was thrown there by the gravitational forces of Jupiter and Saturn. So far away, Planet Nine needs from 10 to 20 thousand years to make one complete revolution around the Sun. Provided that it exists, because until we will have a confirmation through the direct observation by a telescope or a probe, caution remains high.