SETI Institute astronomer, NASA Cassini mission scientist, discoverer of moons.
SETI Institute astronomer Mark Showalter studies the dynamics of rings and small moons in the Solar System. Known for his persistence in planetary image analysis, Mark's early work with Voyager data led to the discoveries of Jupiter's faint, outer "gossamer" rings and Saturn's tiny ring-moon, Pan. Starting in 2003, his work with the Hubble Space Telescope led to the discoveries of "Mab" and "Cupid," small moons of Uranus now named after characters from Shakespeare's plays. His work also revealed two faint outer rings of dust encircling the planet. In 2011, Mark initiated a Hubble observing program focused on Pluto, which led to the discoveries of two tiny moons. Their names, "Kerberos" and "Styx", were selected through an international naming campaign. More recently, Mark discovered the 14th known moon of Neptune, which is designated "S/2004 N 1" until its permanent name can be selected. He is a co-investigator on NASA's Cassini mission to Saturn and its New Horizons mission to Pluto and the Kuiper belt. Following the New Horizons flyby in July 2015, he has been continuing to study the formation and peculiar dynamics of Pluto's moons.