Michael E. Brown

In January 2016, Brown and fellow Caltech astronomer, Konstantin Batygin, proposed the existence of Planet Nine, a major planet between the size of Earth and Neptune. The two astronomers gave a recorded interview in which they described their method and reasoning for proposing Planet 9 on January 20, 2016.

Michael Brown is credited by the Minor Planet Center with the discovery or co-discovery of 29 minor planets (see list below). He is best known in the scientific community for his surveys for distant objects orbiting the Sun. His team has discovered many trans-Neptunian objects (TNOs). Particularly notable are Eris, a dwarf planet and the only TNO known to be more massive than Pluto, leading directly to Pluto's demotion from planet status; Sedna, a planetoid thought to be the first observed body of the inner Öpik–Oort cloud; and Orcus. Brown's team famously named Eris and its moon Dysnomia with the informal names Xena and Gabrielle, respectively, after the two main characters of Xena: Warrior Princess. Together with Jean-Luc Margot in 2001, he also discovered Romulus and Linus, two minor-planet moons in the asteroid belt.

He has been referred to by himself and by others as the man who "killed Pluto", because he furthered Pluto 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 X. Luu 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."

In 2010 Brown published a memoir of his discoveries and surrounding family life, How I Killed Pluto and Why It Had It Coming.

The then director of the IAA, José Carlos del Toro, distanced himself from Ortiz, insisting that its researchers have "sole responsibility" for themselves. Brown petitioned the International Astronomical Union to credit his team rather than Ortiz as the discoverers of Haumea. The IAU has deliberately not acknowledged a discoverer of Haumea. The discovery date and location are listed as March 7, 2003 at Ortiz's Sierra Nevada Observatory. However, the IAU accepted Brown's suggested name of Haumea, which fit the names of Haumea's two moons, rather than Ortiz's Ataecina.

Brown married Diane Binney on March 1, 2003. They have one daughter.

Brown was named one of Time's 100 most influential people of 2006. In 2007 he received Caltech's annual Feynman Prize, Caltech's most prestigious teaching honor. Asteroid 11714 Mikebrown, discovered on April 28, 1998, was named in his honor. In 2012, Brown was awarded the Kavli Prize in Astrophysics.

Brown is a Huntsville, Alabama native and graduated from Virgil I. Grissom High School in 1983. He earned his A.B. in physics from Princeton University in 1987, where he was a member of the Princeton Tower Club. Brown completed his senior thesis, titled "Simulating the measurement of the correlation function of the Shane-Wirtanen galaxy counts", under the supervision of Edward Groth. He did his graduate studies at the University of California, Berkeley where he earned an M.A. degree in astronomy in 1990 and a Ph.D. degree in astronomy in 1994.

Michael E. Brown (born June 5, 1965) 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), notably the dwarf planet Eris, which was originally thought to be bigger than Pluto.