Planet Nine Planet Nine Planet Nine is a hypothetical planet in the outer region of the Solar System. Its gravity could explain the unlikely clustering of orbits for a group of extreme trans-Neptunian objects (eTNOs) that orbit beyond Neptune with average distances greater than 250 AU. These eTNOs tend to have their points of closest approach to the Sun clustered in one direction, and many of their orbits have a similar tilt. This evidence suggests that the gravity from a large undiscovered object is influencing the orbits of the most distant known Solar System objects. This undiscovered super-Earth-sized planet would have an
55 Cancri f IAU announced the winning name was Harriot for this planet. The winning name was submitted by the Royal Netherlands Association for Meteorology and Astronomy of the Netherlands. It honors the astronomer Thomas Harriot. The initial presentation of this planet occurred at a meeting of the American Astronomical Society in April 2005, however it was another two and a half years before the planet was to be published in a peer-reviewed journal. It is the first known planet outside our solar system to spend its entire orbit within what astronomers call the "habitable zone". Furthermore, its discovery made 55 Cancri the