General Physics Colloquium, Prof. David Stevenson, Caltech, AD White Professor-at-Large, Cornell University

Refreshments:

Title:  Jupiter's Interior as Revealed by Juno

Host:  Jonathan Lunine

Abstract: Jupiter is in the class of planets that we call gas giants, not because they consist of gas but because they were primarily made from hydrogen-helium gas, which upon gravitational compression becomes a metallic fluid. Juno, in orbit about Jupiter since 2016, has changed our view: The planet may have a diluted central concentration of heavy elements, consistent with current ideas of formation. It has winds that are limited by magnetic effects but extend to ~3000km in-depth and are evident in the gravity field.  It has a distinctive magnetic field and evidence for secular variation consistent with those winds, and an atmosphere that is surprisingly inhomogeneous because of the peculiarities of the water-ammonia phase diagram. However, Juno is ongoing; it has not answered all questions and has posed new ones.

About David J. Stevenson

David J. Stevenson (Ph.D. ’76) is the Marvin L. Goldberger Professor of Planetary Science at the California Institute of Technology. Stevenson is a world-class scientist, renowned for his creative ideas and contributions of original research in a broad span of areas centering on planetary science but extending as well to geophysics and astrophysics. He has conducted pioneering work in Earth Science (such as the nature of the Earth’s core, mantle convection, and the generation of magnetic fields), planetary science (the interiors of planets, the origin and evolution of icy satellites, and the origin of the Moon), and astrophysics (behavior of degenerate matter and ohmic heating of extra-solar planets, among other problems).   

Stevenson’s curiosity-driven approach to problem-solving has led him from classical questions in geophysics to more novel ones such as whether free-floating planets might be habitable, and how one might sample directly the core of the Earth.

In addition to being a gifted researcher, Stevenson is a highly respected and inspiring teacher as evidenced by being awarded the Richard P. Feynman Prize for excellence in teaching, California Institute of Technology’s highest honor for teaching. He has a passion for sharing his scientific research, and his remarkably lucid explanations of how physical processes work that grace all his talks from public lectures to classes, to technical scientific presentations.

Stevenson received his Ph.D. in Physics from Cornell University in 1976.