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GPS at a Glance

The Division of Geological and Planetary Sciences (GPS) is one of the six academic divisions at Caltech. GPS was established in 1926.

By the Numbers

  • Professorial Faculty: 45
  • Emeritus Faculty: 12
  • Undergraduate Students: 18
  • Graduate Students: 130
  • Postdocs: 81

Academic Programs

Undergraduate Degrees

  • BS in Geobiology
  • BS in Geochemistry
  • BS in Geology
  • BS in Geophysics
  • BS in Planetary Science

Graduate Degrees

  • MS, PhD in Environmental Science and Engineering
  • MS, PhD in Geobiology
  • MS, PhD in Geochemistry
  • MS, PhD in Geology
  • MS, PhD in Geophysics
  • MS, PhD in Planetary Science

The MS is awarded under special circumstances only.

Faculty and Alumni Honors & Awards

  • 3 - American Academy of Arts and Sciences
  • 5 - National Academy of Sciences
  • 5 - AGU Fellow
  • 1 - Macelwane Medal
  • 1 - Kavli Prize
  • 2 - Keiiti Aki Young Scientist Award
  • 2 - MacArthur Fellow
  • 3 - Packard Fellow
  • 1 - Roebling Medal
  • 1 - Wollaston Medal

GPS Rankings

  • No. 1 earth science graduate program in the nation for more than a decade, U.S. News and World Report
  • No. 1 geochemistry, geophysics, and seismology graduate program, U.S. News and World Report, 2014 
  • A top-5 graduate environmental science and engineering program, National Research Council, 2012


  • Geophysicist Charles Richter (PhD '28) developed the Richter scale for measuring earthquakes in the 1930s; in the 1970s, geophysics professor emeritus Hiroo Kanamori and seismologist Thomas C. Hanks created a more accurate scale for measuring large quakes.
  • Geologist and geophysics professor emeritus Gerald Wasserburg's research, which he began in the 1950s, led to the first timeline of the early solar system's development. He was also among the initial scientists to analyze the first lunar rock samples returned to the earth and was instrumental in convincing the government to invest in the study of these samples. 
  • In 2003, planetary science professor Mike Brown discovered the largest object in the Kuiper Belt—a dwarf planet called Eris—which subsequently led to Pluto's demotion from planet to dwarf planet.
  • Astrophysics and planetary science professor emeritus Peter Goldreich's research throughout the 1960s provided key theoretical insights into the structure and mechanics of the solar system, helping scientists build an understanding of how planets form, migrate, and evolve. 
  • Geology professor emeritus Lee Silver (PhD '55) instructed the Apollo 13, 15, 16, and 17 astronauts on how to perform field geology; he is credited with creating lunar field geology as a new discipline and with significantly improving the Apollo missions' scientific returns.
  • The scientific team led by geology professor John Grotzinger, former lead project scientist on the Mars Science Laboratory mission, has analyzed data returned from the Curiosity rover since August 2011, and has found evidence that the martian environment could have supported microbial life billions of years ago.
  • Research conducted during the 1960s and 1970s by geophysics professor emeritus Don Anderson (MS '59, PhD '62) led to a new understanding of the large-scale structure of the earth's interior. His research into the earth's material structure used data generated from seismological studies.
  • Alumnus Walter Munk (BS '39, MS '40) used lessons learned from his geophysics studies at Caltech to shed light on ocean currents, tides, and waves, and their roles in the earth's dynamics.
  • The late geology professor Robert Sharp (BS '34, MS '35) is credited with helping tie earth science research to the study of other planets, Mars in particular. Research done throughout his career illuminated the nature and origin of planetary surfaces, including basin and range structures, glaciers, sand dunes, and landslides and mud flows. 
  • Geology professor (and Caltech interim president, 2013-2014 and provost, 2008-2017) Edward Stolper was the first geologist to identify a rock sample found on the earth as a martian meteorite. 
  • The late geochemistry professor Clair Patterson was the first to determine—in 1953—that the earth and solar system are 4.6 billion years old. In the 1960s, he also provided the first scientific evidence that environmental lead accumulates in the human body, resulting in significant health risks. His findings prompted new regulations in the U.S. auto, gasoline, and paint industries. 
  • Geochemistry professor John Eiler in 2010 created a paleothermometer that uses isotope clumping to determine temperatures in rocks and fossils; he and his colleagues have used this thermometer to measure ancient climates on the earth and Mars, and to pinpoint, for the first time ever, the body temperature of a dinosaur.