In a not so far past there were nine planet names reconized in astronomy in our Solar System. During the 26th General Assembly of International Astronomical Union, the term „planet“ has been fomally defined in the 2006. This very definition caused the reclassification of Pluto from a classical planet to a dwarf planet. A verified expert information appeared about 2 years ago that there is a possible presence of another planet far beyond Neptune’s path. Can we say again that there is a ninth planet in our Solar System? The answer is no. The planet number nine hasn’t been given a precise name and its existence hasn’t been even proven yet. However a detailed computer simulation and analysis of six objects‘ paths, far beyond the Neptune’s path, have arisen some thoughts that there should be such a planet.

Kuiper Belt

It is well known that beyond the planet Neptune there are various space objects with different properties, size, composition and orbiting around certain paths. We call them transneptunian bodies. There is a Kuiper Belt made up of many space bodies within a distance of about 50 AU and the dwarf planet Pluto is included as well. Pluto has been among nine planets of the Solar System not long time ago. Much, much further is the Oort cloud, which is the reservoir of cometary cores. Objects of Kuiper Belt began to be discovered by astronomers in the 90s of the last century. Some of the lately discovered objects run on some strange paths. These can be distant up to hundreds of AUs away from the Sun. The cause of this anomaly was unknown. They thought that it is not related to the gravitational influence of Neptune back then. However we are quite certain now that it is a potential gravitational influence of Planet Nine.

We can soon expect nine names of planets

The naming of the hypothetical ninth planet of our Solar System is not yet definitively known. The name Planet Nine is just a work name introduced by its two main discoverers. The official name won’t be accepted until the presence of this planet is confirmed by optical images. The ninth planet existence is based on mathematical and simulation models so far. After its actual visual confirmation, the IAU will search for its officially confirmed name. As it has been dobe in the past, the name of the planet proposed by its discoverers will be taken into consideration. However, it is quite likely that the name for the new planet will be selected from Roman or Greek mythology. If such naming approach will come true, all names of planets of our Solar System will be connected to mythological characters but our planet Earth.

What is the nature of Planet Nine?

It is estimated that the Planet Nine shape would be very elongated with an eccentricity of 0.6. From the distance point of view, it approaches the Sun 200 AU the closest and the furthest about 1 200 AU. We are talking about a really great distance if we take into comparison the planet Neptune, which is in its orbit at most about 30 AU. Then we have for example the dwarf planet Pluto which can reach a maximum of 49 AU from the Sun. One orbit of the ninth planet around the parent star Sun could be 10 to 20 thousand years. Amateur astronomers now and then ask, whether the discussed planetary object in the outer part of our Solar System is a gaseous giant or a terrestrial type planet. It is interesting to compare the discoveries of the so called extrasolar planets that occur far beyond the Solar System. Some of the expanded group of exoplanets are objects that have the so called “Earth-like character”. Their exact definition, of course, does not yet exist and will not be soon either. However, we can assume that Planet Nine is a planet with a mass greater than Earth and at the same time less than ten times the mass of our planet. The Planet Nine most likely will not be an earth like planet.