Michael E. Brown is an American astronomer, who has been professor of planetary astronomy at the California Institute of Technology (CalTech) since 2003. His team has discovered many trans-Neptunian objects (TNOs), including the dwarf planet Eris, which was originally thought to be bigger than Pluto, triggering a debate on the definition of a planet.
He has been referred to by himself and by others as the man who "killed Pluto", because he furthered Pluto's being downgraded to a dwarf planet in the aftermath of his discovery of Eris and several other probable trans-Neptunian dwarf planets. He is the author of How I Killed Pluto and Why It Had It Coming, published in 2010. He was awarded the Kavli Prize (shared with Jane Lou and David C. Jewitt) in 2012 "for discovering and characterizing the Kuiper Belt and its largest members, work that led to a major advance in the understanding of the history of our planetary system."