Top: Donald Helmberger, Andrew Lange
Bottom: Stephen Mayo, David Stevenson

Four faculty named to NAS

Four Caltech professors are among the 72 new members and 18 foreign associates named to the National Academy of Sciences on April 20. The election was announced during the academy’s 141st annual meeting in Washington, D.C.

Caltech’s new members are Donald Helmberger, Smits Family Professor of
Geological and Planetary Sciences; Andrew Lange, Goldberger Professor of Physics; and Stephen Mayo, professor of biology and chemistry and Howard Hughes Medical Institute associate investigator. David Stevenson, Van Osdol Professor of Planetary Science and a native of New Zealand, was named a foreign associate.

In addition, five Caltech graduates—Paul Chaikin, BS ’66; Andrea Ghez, MS ’89, PhD ’93; Raymond Jeanloz, PhD ’80; Alan Title, PhD ’66; and Margaret Tolbert, PhD ’86—were also named members.
Helmberger’s primary research interests are seismic wave propagation and the inversion of waveforms to recover detailed information about earthquake characteristics and Earth structure. He is interested in mapping ultralow velocity zones at the core-mantle boundary and inner-core structure.

The former director of Caltech’s Seismological Laboratory, Helmberger has been a member of the faculty since 1970 and previously was a research associate at MIT and an assistant professor at Princeton University. In 1997 he became the first recipient of the American Geophysical Union’s Inge Lehmann Medal.

Lange is a cosmologist who has pioneered new techniques for studying the cosmic microwave background radiation, a relic of the primeval “fireball” that filled the universe at the time of the Big Bang. He has used telescopes deployed on high-altitude balloons over Antarctica to determine the fundamental geometry and composition of the universe.

A Caltech faculty member since 1994, Lange was previously an associate professor at UC Berkeley. He earned his BA degree at Princeton, and his PhD at Berkeley. He was cowinner of the California Scientist of the Year honor in 2003.

A faculty member since 1992, Mayo has worked for the last several years on a system for designing, building, and testing proteins with novel biochemical properties. The system automatically determines a string of amino acids that will fold to most nearly duplicate the 3-D shape of a target structure.

Mayo earned his BS in chemistry at Pennsylvania State University, and his PhD in chemistry at Caltech in 1987. As a graduate student, he cofounded the company Molecular Simulations Inc. in 1985, and served as its vice president for biological sciences from 1989 to 1990. Mayo also cofounded Xencor in 1997 and serves on its scientific advisory board.

Stevenson, a Caltech faculty member since 1980, works in the field of theoretical planetary science, employing techniques from fields such as condensed-matter physics and fluid dynamics to better understand Earth, the other planets, and their moons. Much of his research involves interpreting data from spacecraft such as Galileo, which orbited Jupiter, but he is also involved in work on the nature and evolution of Earth’s deep interior.

Stevenson earned his PhD in theoretical physics from Cornell University, and was a member of the UCLA faculty before joining Caltech. He is the winner of the Whipple Award and the Hess Medal from the American Geophysical Union, and was honored by the late Gene Shoemaker, his wife Caroline, and A. Harris with the naming of the asteroid 5211 Stevenson to commemorate his work in planetary science.

The appointments bring to 70 the number of living Caltech faculty who are academy members. In addition, three current Caltech Trustees are members.

With membership long considered one of the highest honors an American scientist can achieve, the National Academy of Sciences is dedicated to the “furtherance of science and its use for the general welfare.” Established in 1863, the academy acts as “an official adviser to the federal government, upon request, in any matter of science and technology.”
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