http://www.sciencemag.org/news/2016/01/feature-astronomers-say-neptune-sized... "Astronomers say a Neptune-sized planet lurks beyond Pluto" allegedly its period is 15000 years, its mass is 5-to-15 earth masses, and its orbit is highly elliptical, unlike Neptune and every planet inside Neptune's orbit, all of which have highly circular orbits. Konstantin Batygin and Mike Brown of the California Institute of Technology (Caltech) in Pasadena are the ones making the claim. However, they have not actually directly seen the planet with any telescope, it is purely a mathematical deduction (similar to LeVerrier and Adams inferring Uranus had to exist) based on the way it appears to be pulling on other planets that we have seen. Actually seeing it could be pretty difficult. -- Warren D. Smith http://RangeVoting.org <-- add your endorsement (by clicking "endorse" as 1st step)