Astronomers at the University of Michigan have suggested that the ninth planet of the solar system may not exist, and the main evidence for its presence is the result of a systematic observation error. A refutation of the presence of a large comic object far beyond the orbit of Neptune is published in the arXiv.org preprint repository.
The hypothesis about the possible existence of Planet X is based on the orbits of the so-called extreme trans-Neptunian objects (ETNO), which are characterized by extended elliptical orbits and do not approach the Sun closer than 30 astronomical units (the distance from the Sun to Neptune). The far points of their orbits are 150 astronomical units away. Astronomers Konstantin Batygin and Michael Brown of the California Institute of Technology found that the perihelions (orbital points closest to the Sun) of ETNO are shifted by the same angle. The simulation results showed that this is a sign of the influence of a large planet.
According to calculations, the mass of the ninth planet in the solar system should be approximately 5-10 times the mass of the Earth and rotate in orbit at a distance of 400 to 800 astronomical units.
According to the assumption of another group of researchers, since ETNOs move in highly elliptical orbits, they can be detected under certain conditions in a limited area of the sky and at a limited distance. The original modeling was based on just six objects. In the new study, scientists analyzed the orbits of a larger sample of ETNO and found that their orbits correspond to a uniform distribution of celestial bodies. Thus, experts concluded, the existence of Planet X cannot be inferred from data on trans-Neptunian objects.