American astronomer and professor of planetary astronomy at the California Institute of Technology (born 1965) who was instrumental in Pluto being downgraded to a dwarf planet in the aftermath of the discovery of Eris and several other probable trans-Neptunian dwarf planets. Two color glossy 10 x 8 photos of astronomer Mike Brown, with one of him during a presentation and the other of Brown surrounded by planets and holding Camilla the rubber chicken, both signed in gold ink. Also includes an ANS on Caltech stationery, which reads: "I think my greatest achievement (so far?) was the discovery & recognition of the importance of Sedna!" In overall fine condition. Accompanied by a personal California Institute of Technology business card belonging to Brown, who has signed the card in blue ballpoint.