Sandra Faber

Lore & Background

Faber studied at Swarthmore College, majoring in physics and minoring in mathematics and astronomy, earning her bachelor's degree in 1966. She earned her PhD in 1972 from Harvard University, specializing in Optical Observational Astronomy under I. John Danziger. During this time, the only observatory open to her was the Kitt Peak National Observatory, which had inadequate technology for the complexity of her thesis. She married Andrew Leigh Faber, a fellow Swarthmore physics major one year her junior, on June 9, 1967; they have two daughters, Robin and Holly. In 1972, Faber joined the faculty of the Lick Observatory at University of California, Santa Cruz, becoming the first woman on staff. In 1976, she observed the relationship between the brightness and spectra of galaxies and the orbital speeds and motions of the stars within them, leading to the Faber–Jackson relation with graduate student Robert Jackson. Three years later, she and John S. Gallagher published a paper collecting all evidence for the existence of dark matter. In 1983, she published original research showing that dark matter was not composed of fast-moving neutrinos ("hot dark matter") but was likely composed of slow-moving particles yet to be discovered ("cold dark matter"). Around 1984, she collaborated with Joel Primack, George R. Blumenthal, and Martin Rees to elucidate the first proposal of how galaxies formed and evolved from the Big Bang. In 1985, Faber was involved with the construction of the Keck Telescope and building the first wide-field planetary camera for the Hubble Space Telescope. She co-chaired the Science Steering Committee for Keck I and insisted on high optical quality for its primary mirror. During the later 1980s, Faber participated in the "Seven Samurai" collaboration, which developed a way to estimate the distance to any galaxy. In 1990, she assisted with the on-orbit commissioning of the wide field planetary camera for the Hubble Space Telescope and helped diagnose the cause of its spherical aberration. She was principal investigator of the Nuker Team, which used the Hubble Space Telescope to search for supermassive black holes at the centers of galaxies. She led the development of the DEIMOS instrument on the Keck telescopes. On August 1, 2012, she became the Interim Director of the University of California Observatories. She co-edited the Annual Review of Astronomy and Astrophysics with Ewine van Dishoeck from 2012 to 2021 and co-chairs the Board of Directors of Annual Reviews.

Reader's Guide

Sandra Faber's career spans fundamental contributions to galaxy evolution, dark matter, and astronomical instrumentation. Her co-discovery of the Faber–Jackson relation established a key link between galaxy brightness and stellar motions, a tool still used to measure cosmic distances. Her early work on dark matter helped shift the paradigm from hot to cold dark matter, shaping modern cosmology. She was instrumental in the design and advocacy of the Keck telescopes, which remain among the world's largest optical telescopes. Her leadership on the Hubble Space Telescope's camera and diagnosis of its spherical aberration were critical to the observatory's success. Through collaborations like the Seven Samurai and the Nuker Team, she advanced methods for measuring galaxy distances and detecting supermassive black holes. Her honors include the National Medal of Science, the Bruce Medal, and the Gold Medal of the Royal Astronomical Society. Faber's legacy is that of a pioneering astrophysicist who combined theoretical insight with hands-on instrument development, influencing both our understanding of the universe and the tools used to explore it.

Did You Know?

• Faber was the first woman on the staff of the Lick Observatory when she joined the faculty in 1972.
• She helped diagnose the spherical aberration in the Hubble Space Telescope's optics during its on-orbit commissioning in 1990.
• Faber co-chaired the Science Steering Committee that oversaw the first-light instrument for the Keck I telescope.
• A minor planet, 283277 Faber, is named for her.
• She co-edited the Annual Review of Astronomy and Astrophysics with Ewine van Dishoeck from 2012 to 2021.

Pioneering Galaxy Physics and the Nature of Dark Matter

Sandra Faber's research career, anchored at the Lick Observatory and the University of California, Santa Cruz, reshaped how astronomers understand the universe's largest structures. She joined the UCSC faculty in 1972 as the first woman on the observatory's staff, a position that would define decades of groundbreaking work. In 1976, she and graduate student Robert Jackson identified a fundamental relationship between a galaxy's luminosity and the orbital speeds of its stars, a result now immortalized as the Faber–Jackson relation. Her work on dark matter proved equally transformative. Gallagher published a paper collecting all of the evidence for the existence of dark matter that had been published at that point, and by 1983 she had published original research arguing that this unseen mass consisted of slow-moving, undiscovered particles rather than fast-moving neutrinos. Around 1984, Faber joined forces with Joel Primack, George R. Blumenthal, and Martin Rees to propose the first comprehensive model of how galaxies formed and evolved from the Big Bang onward—a framework that, despite some corrected details, remains the working paradigm for cosmic structure to this day.

Building the Eyes of Modern Astronomy

Faber's influence extended far beyond the telescope eyepiece into the very construction of the instruments that define modern observational astronomy. Beginning around 1985, she became deeply involved in the design and realization of the Keck telescopes in Hawaii, helping to sell the idea of large optical telescopes all over the world. The Keck I, with its ten-meter primary mirror composed of thirty-six hexagonal segments, became the second-largest optical telescope on Earth, and Faber co-chaired the Science Steering Committee that oversaw its first-light instrument. She persistently insisted on high optical quality for the primary mirror of the Keck I and went on to work on the Keck II as well. In 1985 she also helped build the first wide-field planetary camera destined for the Hubble Space Telescope. When Hubble reached orbit in 1990, she assisted with its on-orbit commissioning and, crucially, helped her team diagnose the cause as spherical aberration. She has described this phase as one of the most exhilarating and well-known phases of her career. Later, her team added a new optical spectrograph to the Keck II in 1996, boosting its capacity to observe far-away galaxies by thirteen-fold.

A Legacy Written in Stars and Honors

The breadth of Faber's contributions is matched only by the recognition they have drawn. Her 1984 collaboration on galaxy formation remains the foundational model for understanding cosmic structure, while her involvement in the eight-year Seven Samurai project—though it fell short of cataloguing all 400 target galaxies—yielded a method for estimating galactic distances that became one of the most reliable ways to measure the total density of the universe. As principal investigator of the Nuker Team, she used the Hubble Space Telescope to hunt for supermassive black holes at galactic centers, and she led development of the DEIMOS instrument on the Keck telescopes for obtaining spectra of cosmologically distant galaxies. Her leadership roles expanded to serving as Interim Director of the University of California Observatories on August 1, 2012, co-editing the Annual Review of Astronomy and Astrophysics with Ewine van Dishoeck from 2012 to 2021, and co-chairing the Board of Directors of Annual Reviews. The honors reflect this reach: the National Medal of Science in 2012, the Royal Astronomical Society's Gold Medal in 2020, the Gruber Prize in Cosmology in 2017, and election to the National Academy of Sciences in 1985, the American Philosophical Society in 2001, and the American Academy of Arts and Sciences in 1989. A minor planet, 283277 Faber, is named for her.

From Swarthmore to the Stars: A Personal Journey

Born Sandra Moore on December 28, 1944, Faber's path to the frontiers of astrophysics began in the classroom. She pursued physics at Swarthmore College, supplementing her studies with minors in mathematics and astronomy, and earned her bachelor's degree in 1966. Her doctoral work at Harvard, completed in 1972 under the guidance of I. John Danziger in Optical Observational Astronomy, was not without obstacles: the only observatory open to her was the Kitt Peak National Observatory, which had inadequate technology for the complexity of her thesis. On June 9, 1967, she married Andrew Leigh Faber, a fellow Swarthmore physics major one year her junior, and the couple went on to raise two daughters, Robin and Holly. Her professional identity became inseparable from UC Santa Cruz, where she rose to the rank of University Professor in 1995 and later became University Professor emerita. Beyond her research, she has served on the Board of Trustees of the Carnegie Institution for Science and has received honorary degrees from Swarthmore College in 1986, Williams College in 1997, the University of Chicago in 2006, the University of Pennsylvania in 2010, and the University of Michigan in 2011.