A small team of planetary scientists from the California Institute of Technology, Université Côte d'Azur and Southwest Research Institute reports possible new evidence of Planet 9. They have published their paper on the arXiv preprint server, and it has been accepted for publication in The Astrophysical Journal Letters.
Because back in my (our) day Pluto was number, so Planet X worked. Planet VIIII doesn’t look as good.
I know. I wasn’t being serious.