Andrea Ghez

Andrea Ghez
Born	6/16/1965
Birthplace	New York City, New York, U.S.
Nationality	American
Occupation	Astrophysicist, professor
Title	Lauren B. Leichtman and Arthur E. Levine Professor of Astrophysics
Employer	University of California, Los Angeles
Known for	Discovery of a supermassive black hole at the center of the Milky Way
Education	B.S. in physics (Massachusetts Institute of Technology); Ph.D. in physics (California Institute of Technology)
Awards	Nobel Prize in Physics (2020), MacArthur Fellowship, Crafoord Prize, Newton Lacy Pierce Prize

Andrea Mia Ghez (born June 16, 1965) is an American astrophysicist and professor at the University of California, Los Angeles (UCLA). She holds the title of Lauren B. Leichtman and Arthur E. Levine Professor of Astrophysics and directs the UCLA Galactic Center Group. In 2020, she shared the Nobel Prize in Physics with Roger Penrose and Reinhard Genzel for discoveries relating to black holes. Specifically, she was recognized "for the discovery of a supermassive compact object at the centre of our galaxy."

She made history as the fourth woman to win the Nobel Prize in Physics, following Marie Curie (1903), Maria Goeppert Mayer (1963), and Donna Strickland (2018). Her research has centered on tracking the orbits of stars at the heart of the Milky Way using the W. M. Keck Observatory in Hawaii. This decades-long pursuit yielded the strongest observational evidence that a supermassive black hole, now called Sagittarius A*, sits at the galactic center, with a mass of approximately four million times that of the Sun. Her research has fundamentally reshaped the understanding of galactic nuclei and the role supermassive black holes play in the structure and evolution of galaxies.

Early life

Andrea Mia Ghez was born on June 16, 1965, in New York City, New York. She came of age during the Apollo space program, and the Moon landings beginning in 1969 left a deep mark on her childhood ambitions. As a young girl, she dreamed of becoming an astronaut, and her mother bought her a telescope, nurturing that early curiosity about the cosmos. That early exposure planted the foundation for a lifetime of studying the universe.

Her path into professional science was not without friction. Early in her career, skeptics questioned whether her proposed research program — observing and characterizing the environment at the Milky Way's center — was even feasible. Those doubts did not deter her. Her childhood fascination and determination propelled her into an academic career that would eventually produce one of the most consequential discoveries in modern astrophysics.

Education

Ghez earned her Bachelor of Science in physics from the Massachusetts Institute of Technology (MIT). She then pursued graduate work at the California Institute of Technology (Caltech), completing her Ph.D. in physics under the supervision of Gerry Neugebauer. Her doctoral research introduced her to high-resolution imaging and infrared astronomy, disciplines that would become central to her later work on the galactic center. At Caltech, she developed expertise in speckle imaging, a technique that allows ground-based telescopes to overcome atmospheric distortion and achieve near-diffraction-limited resolution by combining many short-exposure photographs. This observational capability would anchor her research approach for decades.

Career

UCLA and the Galactic Center Group

After completing her doctorate, Ghez joined the faculty at UCLA in 1994. She rose to become the Lauren B. Leichtman and Arthur E. Levine Professor of Astrophysics. At UCLA, she founded the Galactic Center Group, a research team devoted to studying the astrophysical environment at the heart of the Milky Way.

The central question driving her research program was whether a supermassive black hole resides at the galaxy's core. Theoretical predictions and indirect evidence had long pointed to an enormously massive, compact object in the region designated Sagittarius A* (Sgr A*), but direct observational proof had remained elusive. Interstellar dust absorbs and scatters visible light, making the galactic center opaque to conventional optical telescopes. Ghez's solution was to observe in the near-infrared portion of the electromagnetic spectrum, which penetrates dust, combining that approach with the world's most powerful telescopes and the latest high-resolution imaging techniques to resolve individual stars orbiting the galactic center.

Observations at the W. M. Keck Observatory

The W. M. Keck Observatory, situated atop Mauna Kea in Hawaii, became her primary instrument. The facility houses two 10-meter telescopes, among the largest optical and infrared telescopes in the world. Ghez and her team equipped them with adaptive optics systems that correct for atmospheric distortion in real time by adjusting a deformable mirror hundreds of times per second, producing extraordinarily sharp images of the stars nearest Sagittarius A*.

From the mid-1990s onward, Ghez and her collaborators conducted a long-term monitoring campaign, tracking the positions and motions of stars in the immediate vicinity of Sagittarius A*. One star proved especially important: S0-2, also known as S2, which follows a highly elliptical orbit with a period of approximately 16 years, passing within a few light-hours of the central object at closest approach. In 1998, Ghez and her team published results in The Astrophysical Journal demonstrating that the proper motions of stars near the galactic center were consistent with the presence of a massive dark object.

By tracking S0-2 and other stars through significant portions of their orbits, the team applied Kepler's laws to calculate the mass of the central object. The result was approximately four million solar masses concentrated in a region so compact that a supermassive black hole remains the only physically consistent explanation. This work was conducted independently and in parallel with a comparable program led by Reinhard Genzel at the Max Planck Institute for Extraterrestrial Physics in Germany. Together, the two research groups provided the most compelling observational case that supermassive black holes exist not merely as theoretical predictions of general relativity, but as physical objects at the centers of galaxies.

Advancing adaptive optics and infrared techniques

Ghez's contributions to astrophysics extend beyond her specific discoveries to encompass fundamental advances in observational methodology. Early in her career, she employed speckle imaging, reconstructing sharp images by combining many short-exposure photographs to strip away the blurring effects of the atmosphere. As technology advanced, she became a leading practitioner of adaptive optics, achieving angular resolution at Keck comparable to the Hubble Space Telescope, but with substantially greater light-gathering power in the infrared. Without these advances in instrumentation and technique, measuring the minute positional shifts of individual stars over time — shifts that reveal the gravitational influence of Sagittarius A* — would not have been possible from the ground.

Testing general relativity

Ghez's observations also opened new avenues for testing Einstein's general theory of relativity under extreme gravitational conditions. Stars such as S0-2 reach speeds of several thousand kilometres per second as they pass close to the black hole, making relativistic effects, including gravitational redshift, directly measurable. Her team used these orbital passages to test whether the predictions of general relativity hold in the powerful gravitational field near a supermassive black hole, contributing to broader efforts to probe the boundaries of Einstein's theory in regimes inaccessible by other means.

Public engagement and lectures

Ghez has maintained an active presence in public scientific discourse beyond her research program. In 2025, she participated in an interdisciplinary panel at the American Academy of Arts and Sciences on "Science and Creativity," examining how innovative thinking drives scientific discovery. In 2026, she was invited to deliver the McDonnell Distinguished Lectures at Washington University in St. Louis, one of a series of high-profile public lectures she has given at universities across the United States. She also presented at Pennsylvania State University's Eberly College of Science, discussing her discovery of the supermassive black hole at the Milky Way's center.

In a Nobel interview, she reflected on the challenges of pursuing a research program that demanded decades of sustained observation and emphasized the importance of persistence in scientific work.

Role at the University of California

Ghez has spoken publicly about the University of California system's importance as an environment for scientific research. In a 2025 feature, she was among several UC Nobel laureates discussing why the university provided fertile ground for breakthrough discoveries, pointing to research infrastructure, access to major observatories including Keck, and UCLA's collaborative culture as essential enablers of her work. She has stressed that the long-term, high-risk observational program that ultimately confirmed Sagittarius A* as a supermassive black hole required sustained institutional support and patience — resources that UCLA provided.

Personal life

Ghez has kept her personal life largely private while living in the Los Angeles area, where she continues her research and teaching at UCLA. In Nobel Prize interviews, she has spoken of balancing an intensive observational research career with family responsibilities and has been candid about navigating a field historically dominated by men. As the fourth woman to win the Nobel Prize in Physics, her achievement carries significance beyond its scientific content in ongoing discussions about gender representation in physics. She has spoken about the skepticism she faced early in her career from those who doubted the feasibility of her research program, and has pointed to persistence and the accumulation of strong observational results as the means by which she overcame it.

Recognition

Nobel Prize in Physics

On October 6, 2020, the Royal Swedish Academy of Sciences announced that Andrea Ghez would share one half of the Nobel Prize in Physics with Reinhard Genzel "for the discovery of a supermassive compact object at the centre of our galaxy," with each receiving one quarter of the total prize. Roger Penrose received the remaining half "for the discovery that black hole formation is a robust prediction of the general theory of relativity." The Nobel Committee emphasized that Ghez's decades-long observational campaign — using the world's largest telescopes equipped with adaptive optics — had delivered definitive proof that an invisible, extremely massive object governs the orbits of stars at the Milky Way's center, and that a supermassive black hole is the only known physical explanation for that phenomenon.

Other awards and honours

Prior to the Nobel Prize, Ghez received extensive recognition for her research. The Royal Swedish Academy of Sciences awarded her the Crafoord Prize in Astronomy, one of the most significant honours in scientific fields outside the Nobel Prize's scope. She was also named a MacArthur Fellow — a so-called "genius grant" — in recognition of exceptional creativity and research promise. Earlier in her career, she received the Newton Lacy Pierce Prize in Astronomy from the American Astronomical Society. The National Academy of Sciences and the American Academy of Arts and Sciences have both elected her to membership in acknowledgment of her outstanding research contributions. The W. M. Keck Observatory has also recognised her for discoveries of fundamental importance to astrophysics made possible through its facilities.

Legacy

Andrea