Michael E. Brown

Lore & Background

Michael E. Brown was raised in Huntsville, Alabama, and graduated from Virgil I. Grissom High School in 1983. He earned an A.B. in physics from Princeton University in 1987, where he was a member of the Tower Club, and completed his senior thesis under Edward J. Groth. He earned an M.A. in astronomy in 1990 and a Ph.D. in astronomy in 1994 from the University of California, Berkeley.

Brown's team discovered many trans-Neptunian objects, including Eris, Sedna, and Orcus. The discovery of Eris, which was initially thought to be larger than Pluto, directly led to Pluto's demotion from planet status. Brown's team informally named Eris and its moon Dysnomia 'Xena' and 'Gabrielle' after characters from the television show Xena: Warrior Princess. He also co-discovered the minor-planet moons Romulus and Linus with Jean-Luc Margot in 2005.

Brown was involved in a controversy over the discovery of the dwarf planet Haumea. His team had observed Haumea for about six months before its announcement by José Luis Ortiz Moreno's team. Brown initially supported Ortiz's team receiving credit, but later investigation showed that computers at Ortiz's institute had accessed Brown's telescope logs before the announcement. The IAU officially lists a discoverer team (J. L. Ortiz et al.) for the March 7, 2003 observation of Haumea, but accepted Brown's suggested name of Haumea.

Reader's Guide

Michael E. Brown's significance lies in his role in reshaping the definition of a planet in the Solar System. His team's discovery of Eris, a trans-Neptunian object initially thought to be more massive than Pluto, forced the International Astronomical Union to formally define what constitutes a planet, resulting in Pluto's reclassification as a dwarf planet in 2006. This decision, which Brown furthered, fundamentally changed public and scientific understanding of the Solar System. Brown also contributed to the discovery of numerous other trans-Neptunian objects, including Sedna and Orcus, and co-proposed the existence of Planet Nine in 2016. His work on the Kuiper belt and its largest members earned him the Kavli Prize in Astrophysics in 2012, shared with Jane Luu and David C. Jewitt. Brown's memoir, How I Killed Pluto and Why It Had It Coming, published in 2010, details his discoveries and their impact. He was named one of Time's 100 most influential people in 2006 and received Caltech's Feynman Prize in 2007. The asteroid 11714 Mikebrown was named in his honor.

Did You Know?

• Brown's team initially referred to Eris and its moon Dysnomia by the informal names Xena and Gabrielle, after characters from Xena: Warrior Princess.
• The Kavli Prize in Astrophysics in 2012 was awarded to Jane Luu and David C. Jewitt; Brown was not a recipient.
• Brown proposed the existence of Planet Nine in January 2016 with fellow Caltech astronomer Konstantin Batygin.
• The IAU accepted Brown's suggested name of Haumea for the dwarf planet, rather than the name Ataecina proposed by the Spanish team.