90 Years of GPS
Highlights from nine decades of alumni impact
In May of 2017, the Division of Geological and Planetary Sciences (GPS) celebrated its 90th anniversary. During those 90 years, GPS faculty have contributed greatly to our understanding of our planet and solar system. From the chronology of solar system evolution to the dynamics of earthquakes to the history of Earth’s oxygenated atmosphere, we have transformed the ways we think and talk about our home in the universe.
It would have been easy and perhaps natural to observe the division’s 90th anniversary by focusing on faculty achievements as we have in the past. But we took a different course with this celebration because two of our graduates turned 100 this year—Mel Levet and Walter Munk—and that seemed reason enough to do something special. As former students, they provided the incentive to focus on our alumni rather than our faculty as we had done for the 75th.
Our alumni have profoundly shaped the fields they entered and will continue to do so in the future. From Walter Munk, whose research laid the foundation for modern oceanography, to Alice Michel, a recent undergrad alumna who rewrote the Wikipedia entry for geobiology, an impressive group of GPS alumni stepped forward to talk about what they learned at Caltech and how they applied it later. Reflecting the array of options in the division, the lineup featured alumni who have gone on to be geobiologists, geochemists, geologists, geophysicists, and planetary scientists as well as investment managers, earthquake engineers, and environmental engineers.
Of course, we were limited by the format—a single day of talks, exhibits, and lab tours. That is why I am excited that this issue of Techer showcases our GPS alumni in all their diversity. As you read through the brief descriptions of who they are and what they have achieved, I hope you are as impressed as I am with the depth and breadth of their accomplishments.
—John P. Grotzinger
Fletcher Jones Professor of Geology;
Ted and Ginger Jenkins Leadership Chair,
Division of Geological and Planetary Sciences
Highlights of GPS Alumni Achievements
Hugo Benioff (PhD ’35) invents the “Benioff seismometer,” which measures the Earth’s movements. Its precision and simplicity—according to a memoir from the National Academy of Sciences—“are responsible for the adoption of this remarkable instrument by observatories all over the world.”
Walter Munk (BS ’39, MS ’40), professor at Scripps Institution of Oceanography at UC San Diego, has been called the “world’s greatest living oceanographer” and the “Einstein of the ocean.” In 1942, Munk and his mentor Harald Sverdrup developed techniques for predicting ocean waves and surf conditions for amphibious warfare that were used by Allied forces to predict wave conditions for the D-Day landings at Normandy.
Munk's contributions to physical oceanography and geophysics have advanced the science and understanding of ocean waves, wind-driven ocean gyres, deep-sea tides, internal waves, the rotation of the Earth, ocean acoustics, and geophysical data analysis.
The first-ever photo flyby of Mars by Mariner 4 is led by Caltech astronomer Robert Leighton (BS ’41, PhD ’47). Also on the team: eventual Caltech geology division chair Robert Sharp (BS ’34, MS ’35) (see 1989).
Caltech professor Lee Silver (PhD ‘55) gave many Apollo astronauts lessons in lunar geology. He taught them what to look for and how to describe what they were seeing on the surface of the moon, in his words, “in clear and simple language, ordered and organized.”
“The astronauts who went to the Moon knew they weren’t just looking for rocks, they were looking for clues to the Moon’s history and, by extension, the history of the Earth, of the solar system, and of all creation.” —Josh Gelernter for The National Review, July 31, 2015
In 1972 Harrison Schmitt (BS ’57) traveled to the moon as a member of the Apollo 17 team—NASA’s final Apollo mission. He would eventually log 301 hours and 51 minutes of space time, and go on to become a US senator from New Mexico.
Larry Soderblom (PhD ’70) has been involved in numerous JPL planetary missions, including the Mariner 6, 7, and 9, Viking, Voyager, Magellan, Galileo, Mars Global Surveyor, Mars Pathfinder, Deep Space 1, Cassini, Huygens, and the Mars Exploration Rovers. From 1978 to 1996, he twice served as Chief of the Branch of Astrogeology of the United States Geological Survey.
Hugh P. Taylor (BS ’54, PhD ’59) is inducted into the National Academy of Sciences. Taylor, the Robert P. Sharp Professor of Geology, Emeritus, was one of the first two geochemistry majors to graduate from Caltech. He served as a member of Caltech’s faculty from 1959 to 2002.
Leon Thomsen (BS ’64) publishes “Weak elastic anisotropy”—which discussed the velocity of seismic waves in rock—in the journal Geophysics. His paper would go on to become the most frequently cited paper in the field’s history. Thomsen is currently the chief scientist at Delta Geophysics.
Robert Sharp (BS ’34, MS ’35) is awarded the National Medal of Science, presented by President George H.W. Bush on the White House lawn. Sharp was honored for “research that has illuminated the nature and origin of the forms and formation processes of planetary surfaces and for teaching two generations of scientists and laymen to appreciate them; for his recruitment and leadership of a successful multidisciplinary department of Earth and planetary scientists who have gained world recognition.”
Along with his wife, Carolyn, and another fellow star searcher, Eugene Shoemaker (BS ’48, MS ’49) co-discovers a comet later to be known as the Comet Shoemaker–Levy 9, which impacted Jupiter in 1994. Shoemaker and his wife are credited together or separately with discovering 1,125 asteroids and 32 comets.
Sue Kieffer (PhD ’71) is named a MacArthur Fellow, with the award noting—among other things—that “she used shock wave theory to analyze the lateral blast at Mount St. Helens in 1980, and was the first to describe the physics and chemistry of the supersonic eruptions on Jupiter’s moon, Io.” She wrote in Engineering & Science in 1981 that her “memories of working at Mount St. Helens during March, April, and May of 1980 should be unscrambled by a psychologist; and only a poet or philosopher could describe the experiences as they deserve.”
Holly Given (PhD ’86) becomes one of the first-ever technical officers of the Comprehensive Nuclear Test Ban Treaty, tasked with establishing procedures for the global stations—everywhere from Kazakhstan to Kenya—responsible for compliance monitoring. Given is currently an executive director in the International Ocean Discovery Program at Scripps Institution of Oceanography.
Croatia native Tanja Bosak (PhD ’04) becomes Caltech’s first graduate student in the field of geobiology. She earned the Subaru Outstanding Woman in Science award from the Geological Society of America in 2007 and the Macelwane Medal from the American Geophysical Union in 2011.
The International Astronomical Union announces the naming of asteroid 4922 Leshin in honor of Laurie Leshin’s (PhD ’94) contributions to planetary science. Since then, her career has included working as deputy director of NASA’s Exploration Systems Mission Directorate, which plans the future of human space flight. Leshin currently serves as the 16th president of Worcester Polytechnic Institute.
Charles Elachi (PhD ’71) is named head of NASA’s Jet Propulsion Laboratory, a position he held for 15 years. That period included everything from three Mars rover missions to the Stardust mission returning with collected comet samples and interstellar material.
Former president of the Seismological Society of America Tom Jordan (BS ’69, PhD ’72) becomes director of the Southern California Earthquake Center. In 2012, he was given the Award for Outstanding Contribution to Public Understanding of the Geosciences by the American Geosciences Institute.
Mike Malin (PhD ’75) and colleague Kenneth Edgett unveil photographic evidence strongly suggesting that water once was flowing on Mars. “Recognizing new contemporary processes is always a thrill,” he told Nature at the time. “The current gully activity was anticipated, but to find it actually happening was very cool.” His company, Malin Space Science Systems (MSSS), has designed cameras for every one of NASA’s Mars-orbiting missions since Viking in 1975.
Geophysicist Sean Solomon (BS ’66) is named a recipient of the National Medal of Science, which he received from President Barack Obama at the White House. He is the director of Columbia University’s Lamont-Doherty Earth Observatory. Solomon has led or been involved in oceanographic expeditions on Earth as well as spacecraft missions to the Moon, Venus, Mars, and Mercury.
Francis A. Macdonald (BS ’01) receives the Geological Society of America Young Scientist Award (Donath Medal) for outstanding achievement in contributing to geologic knowledge through original research that marks a major advance in the Earth Sciences. Macdonald is now a professor of Earth and planetary sciences at Harvard.
Caltech assistant professor of planetary science Konstantin Batygin (PhD ’12) and collaborator professor of planetary astronomy Mike Brown announce signs of a ninth planet in our solar system. “For the first time in over 150 years,” Batygin said, “there is solid evidence that the solar system’s planetary census is incomplete.”
In a paper in Nature, Sarah Stewart (PhD ’02) posits a new theory about the origin of the Earth’s tilt: a collision with a massive, Mars-sized object that not only created the moon but also tipped the Earth over at a 60- to 80-degree angle. “For the first time, this paper has a model that says we can start in one place and explain all of that without invoking any other follow-on event,” Stewart told The New York Times.