A Revolution in Planetary Science: The Three-Zoned Solar System

Abstract

Science’s view of our planetary system was fundamentally restructured by the 1990s discovery of the Kuiper Belt beyond Neptune and the recent discoveries of numerous Pluto-sized bodies in the Kuiper Belt. No longer do we view the solar system’s architecture as inner terrestrial planets and outer gas giants, with misfit Pluto orbiting beyond. Instead, Pluto is now seen in context, being one of many dwarf planets orbiting in a third zone, equally fundamental zone of our planetary system that lies beyond Neptune. I will describe this revolutionary transformation in astronomy’s worldview of our home solar system, as well as its implications for understanding both the taxonomy of solar systems around other stars and also for planet classification.