Planet 9 from Outer Space with Dr. Michael Brown

Dr. Brown (whose discovery of dwarf planet Eris led to the reclassification of Pluto) discusses the history of planetary discovery (and demotion), why we think a new, larger Planet 9 is on the verge of being found, and the techniques that we are using to try to find this very faint body lurking in the far reaches of our planetary system.  This was recorded Nov. 11, 2020.