At https://phys.org/print417340282.html … an online paper currently available at www.arxiv.org/abs/1704.02444 is written by two researchers at the University of Arizona's Lunar and Planetary Laboratory, and claims there may be a planet sized body (somewhere in the region of the size of Mars or the Earth, orbiting in the outer solar system. The hypothesis comes about as a means to explain some orbital inconsistencies amongst distant bodies in the Kuiper Belt region. It is due to be published in the Astronomical Journal and adds a new line to the ongoing debate on Planet X (or variously Planet Nine).
They claim this rules out Planet Nine – envisaged as a much larger object. However, a planet sized body is a big enough to amount to an elephant in the room that has yet to be seen. Why has it not yet being found, what with all those telescopes peering into space. It seems the answer is that it might be hiding in the galactic plane, an area densely packed with stars that solar system surveys tend to avoid. However, they also said that a 'passing star' could draw out the inconsistencies in the distant solar system and a hidden planet is by no means the only explanation. Does this leave room for Rupert Holms' supernova event (see SIS Review 2017:1 and 2016:3)?