Dr. Steven Soter, PhD, is an astrophysicist currently holding the positions of scientist-in-residence for New York University's Environmental Studies Program and of Research Associate for the Department of Astrophysics at the American Museum of Natural History. He is a vocal proponent of the International Astronomical Union's controversial 2006 definition of planet.
Soter received his Bachelors degree in astronomy and physics from UCLA in 1965 and his doctorate in astronomy from Cornell University. One of his advisors was popular astronomer Carl Sagan.
In 1974, Soter suggested that dust produced by meteoritic bombardment of Saturn's moon Phoebe might orbit the planet until colliding with Saturn's moon Iapetus and be responsible for the unique two-toned coloration of the latter.[1] Saturn's "Phoebe ring", discovered in 2009, validated this prediction.
In 1977-1979, he co-wrote Carl Sagan's monumental 1980 astronomy documentary series Cosmos. Since then, he has also acted as advisor on a number of science documentaries, such as the IMAX films Blue Planet and Cosmic Voyage.
In 1997 he took a position at the American Museum of Natural History's Hayden Planetarium, and eventually progressed to the position of research associate.
In 2007, after the IAU announced its controversial decision on the definition of planet, Soter published an article in Scientific American in which he outlined a mathematical formulation, the "planetary discriminant", to describe how the IAU's requirement that a planet must have "cleared its neighborhood" of other objects might be applied in practice. He had already written a more technical article on the same subject in 2006 before the new definition, but published after in The Astronomical Journal