Dr. John Spencer is the 2016 recipient of the Whipple Award, the highest honor given by the American Geophysical Union Planetary Sciences section. Dr. Spencer’s contributions to the exploration and understanding of satellites in the solar system have had a profound influence on the field of planetary science.
Dr. Spencer is a gifted astronomer, who specializes in multispectral observations from ground-based telescopes to spacecraft. He has probed atmospheric compositions, measured tidal heat output, and chased the seasonal dance of surface frosts across the outer solar system. Dr. Spencer’s research into the thermal and physical properties of planetary surfaces has shed light on the most remote terrains.
Dr. Spencer’s research on Io has been vital to our understanding of Jupiter’s intensely volcanic moon. Most notably, his discovery of S2 gas in the large plume, Pele, has been key in constraining Io’s interior chemistry. By exploring Io from multiple flyby spacecraft and from Hubble to monitor major volcanic eruptions and to map global thermal emission, his research has been crucial in constraining Io’s energy budget.
Using Cassini data, Dr. Spencer was first to recognize that excess thermal energy is radiating from the “tiger stripes” region near Enceladus’s south pole from which its plumes erupt. His estimation of the total flux has led to insights into the internal structure, energetics driving the plume, character of the internal ocean, and Enceladus’s tidal evolution.
Dr. Spencer’s leadership on Galileo, Cassini, and now New Horizons has trained a new generation of scientists in rigorous analysis techniques and innovative observing strategies. Dr. Spencer’s enthusiastic support of the planetary community includes chairing the Satellites panel for the last Decadal Survey and laying the groundwork for the Europa mission.
The planetary science community honors Dr. Spencer for his research accomplishments, community spirit, and intense curiosity. We look forward to your discoveries on Europa and the Kuiper Belt!
—Sarah T. Stewart, University of California, Davis
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Evidence from Arrokoth and comets strongly suggests a very low density for this and similar small Kuiper belt objects. Plausible compositions imply...
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