Sally Kristen Ride (May 26, 1951 – July 23, 2012) was an American physicist and astronaut. Born in Los Angeles, Ride joined NASA in 1978 and, at the age of 32, became the first American woman in space. After flying twice on the space shuttle Challenger, she left NASA in 1987. She worked for two years at Stanford University's Center for International Security and Arms Control, then the University of California, San Diego as a professor of physics, primarily researching non-linear optics and Thomson scattering. She served on the committees that investigated the Challenger and Columbia space shuttle disasters, the only person to participate on both.Ride remains the youngest American astronaut to travel to space.
Mike Brown (born 5 June 1965) has been a 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, the only known TNO more massive than Pluto. He has referred to himself as the man who "killed Pluto", because he furthered Pluto being downgraded to a dwarf planet in the aftermath of the 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.