Since the demotion of Pluto to dwarf planet, there’s been a ninth-planet-shaped hole in the hearts of many Earthlings. Though Planet 9 has never been confirmed, we know a lot about what a planet in its suspected area could be like. The furthest known planet, Neptune, is only about 31 AU. Planet 9 would also have an irregular orbit, scientists believe, so it would spent part of its cycle even further away. “The finalist of our Planet Nine candidate pair strongly depends on how the characteristics of Planet Nine are defined.