Originally posted to the Astro Pro channel on January 25, 2023. Buy the map here: https://store.nebula.tv/products/atlas-pro-mars-surface-art-print Today we're looking at the popular myth of Planet X and seeing if there could be any truth behind the claims of there being a ninth planet. Support me on Patreon here: https://www.patreon.com/atlaspro Follow me on Twitter @theatlaspro Sources / Further Reading https://www.history.com/this-day-in-history/pluto-discovered#:~:text=However%2C%20in%201929%2C%20using%20the,combined%20with%20a%20blink%20microscope. https://web.archive.org/web/20141216183818/http://home.dtm.ciw.edu/users/sheppard/pub/TrujilloSheppard2014.pdf https://arxiv.org/abs/1601.05438 https://www.youtube.com/watch?v=WHNO079G1i8&t=3135s https://www.realclearscience.com/lists/unsolved_problems_in_astronomy/kuiper_cliff.html https://solarsystem.nasa.gov/planets/hypothetical-planet-x/in-depth/ https://www.nytimes.com/2016/01/21/science/space/ninth-planet-solar-system-beyond-pluto.html https://arxiv.org/abs/astro-ph/0404456 https://www.newscientist.com/article/mg19726381-600-the-mystery-of-planet-x/