A peer reviewed article published in The Astronomical Journal has provided the best evidence to date for the existence of a 9th planet. According to the authors of the study, a strange cluster of 6 objects beyond the orbit of Neptune has a 0.007 chance of not being caused by an undiscovered planet. The proposed planet has an orbit of around 15,000 years  and is roughly the size of Neptune. The planet’s suggested perihelion would be about 200 AU (AU is the distance from the earth to the sun) and its aphelion could be anywhere from 600-1200 AU (Pluto has a perihelion of 29.7). The Caltech researchers, Konstantin Batygin and Mike Brown, responsible for the discovery have admitted nobody will truly believe it’s there until someone manages to directly observe the distant planet.