David J. Stevenson, Marvin L. Goldberger Professor of Planetary Science, Geological and Planetary Sciences, Caltech
After summarizing our current state of understanding of Earth from the perspective of how it formed & differentiated, I will focus on a problem of current great interest: How can Earth maintain a magnetic field for most of its history? Conventional explanations do not work in light of recent upward revision of the thermal conductivity of the core alloy, which allows core heat to escape by conduction alone, preventing a dynamo. The proposed solution is exsolution: Mantle material coming out of the core, releasing gravitational energy and driving compositional convection. This exsolution is a legacy of Earth's traumatic birth.