There seems to be an unfair amount of giggling in this thread. Brown et al aren't, to my knowledge, simply hoping this hypothetical planet into existence a la

There seems to be an unfair amount of giggling in this thread. Brown et al aren't, to my knowledge, simply hoping this hypothetical planet into existence a la Nibiru. Brown discovered Eris and his handle on Twitter is @plutokiller for a reason. See https://arxiv.org/abs/1603.05712 https://arxiv.org/abs/1603.05712 for previous work. Edit: Adding from the Conclusion The existence of a distant massive perturber in the outer solar system – Planet Nine – explains several hitherto unconnected observations about the outer solar system, including the orbital alignment of the most distant Kuiper belt objects, the existence and alignment of high perihelion objects like Sedna, and the presence of perpendicular high semimajor axis Centaurs. [...] i.e. Planet nine may be Occam's razor for a number of whacky observations.