Professor McKinnon’s research focuses on the icy satellites of the outer solar system and the physics of impact cratering. He and his students and colleagues concentrate on the origin, structure, evolution, and bombardment history of outer planet satellites and Pluto.
The last twenty odd years of planetary exploration can be characterized by both the unveiling of the outer solar system - initially by the Voyager missions, but now by the Galileo mission to Jupiter as well as ground- and space-based telescopes - and the growing realization of the importance of impacts in solar system evolution. Dedicated to exploring this frontier, Professor McKinnon believes this includes understanding the relative importance of large impacts, orbital dynamics, and internal processes for tectonics and other surface modifications, the origin and evolution of impactor populations, and the cratering mechanics in ice and other targets.
Professor McKinnon is interested in extending our geological and geophysical perspectives to worlds where water ice is a major, if not dominant, constituent. These worlds include the satellite systems of Jupiter, Saturn, and Uranus, which resemble miniature solar systems in part. Galileo image and other data received over the last several years has transformed our view of the Jupiter's major moons - Io, Europa, Ganymede and Callisto - in particular. Ganymede and Callisto are especially interesting, as they are very similar in bulk properties, yet startlingly different in appearance. Work has focused on their internal structures, convection in their icy mantles, viscous relaxation of impact crater topography, and on Ganymede, topographic and morphologic evidence for water-rich volcanism. Other work has concerned the links between the extreme volcanism and towering mountains on Io, the solar system's most active solid body.
Of all of the Galilean satellites, though, Europa, with its complexly tectonically and volcanically deformed icy surface and probable subsurface water ocean, has clearly emerged as the star. Active research involves linking the tectonic patterns seen on the surface to sources of stress, the conditions necessary for subsolidus convection within both the surface ice shell and the interior silicate mantle, and the geophysical and geochemical consequences thereof. The latter are of deep interest because of the theoretical possibility of a subsurface biosphere, hosted in hydrothermal systems on Europa's ocean floor.