ALAN STERN, PhD, is a planetary scientist and astrophysicist with both observational and theoretical interests. Dr. Stern is an avid pilot and a principal investigator in NASA's planetary research program, and he was a finalist candidate to become a NASA space shuttle mission specialist. He is the leader of the Southwest Research Institute's Geophysical, Astrophysical, and Planetary Science group, located in Boulder, Colorado. Dr. Stern has published more than 110 technical papers and 20 popular articles. His research has focused on studies of the satellites of the outer planets, Pluto, comets, the Oort Cloud and Kuiper Belt, and the search for evidence of solar systems around other stars.
JACQUELINE MITTON, PhD, lives and works in Cambridge, England. She trained as an astronomer at Oxford and Cambridge Universities and has for many years concentrated on bringing astronomy to the general public, mainly as a writer, and through the media in her role as Public Relations Officer for the Royal Astronomical Society. She is a former editor of the Journal of the British Astronomical Association and the author, coauthor, or contributing editor of 12 previous books, including The Penguin Dictionary of Astronomy, Gems of Hubble, and The Great Comet Crash.