Andrea Mia Ghez

by Jennifer Lauren Lee

Andrea Ghez, professor of astronomy at UCLA. (Andrea Ghez)
Andrea Ghez, professor of astronomy at UCLA. (Andrea Ghez)

As a teen, Andrea Ghez would stay up late at night thinking about the fundamental questions of the universe long before she had the tools to answer them.

"I love the question of what paradoxes you fall into when you start thinking about the big questions," she says enthusiastically. What is the beginning and ending of time? Where is the edge of the universe? How do you come to terms with humanity’s insiginificant hundred-thousand-year-old existence when faced with a universe that is 13 billion years old? Hard questions to resolve, but even as a young girl they fascinated her.

A world-class observational astrophysicist and professor of astronomy at UCLA, Andrea Ghez’s discoveries have won her awards and fellowships, helped get her elected into the highly prestigious National Academy of Sciences, and earned her acclaim in Discover magazine as one of the top 20 young American scientists who "will likely change our fundamental understanding of the world and our place in it."

Working in a field dominated by men, Dr. Ghez turns to strong women figures such as Amelia Earhart for inspiration.

"You have to have a strong sense of self—to believe that it is okay to be playing in this playground," she says.

At one point while growing up in Chicago, young Andrea wanted to be a ballerina. But looking back at her childhood now, she believes part of her was always attracted to the sciences.

"I’m definitely a product of the first moon landings," she says. She laughs. "I think I told my mom I wanted to be the first female astronaut—although that tells you more about my household than it does about me." She explains that her mother was supportive, encouraging her to believe that she could do great things and to push herself to accomplish them.

It wasn’t a clear path from astronaut-ballerina to astrophysicist, but Ghez says she gravitated toward astronomy through her love of math and science.

"I loved math," says Ghez. "I was originally a math major and switched (to physics)."

Dr. Ghez is best known in the scientific community for her revolutionary discoveries concerning star formation and the black hole at the center of our galaxy. She was still a graduate student at Caltech, earning her Ph.D. in physics in the early nineties, when she discovered that most stars in the universe are born with a companion, so that a majority of solar systems have two "suns" instead of one. The discovery that most star systems are binary showed us that we could no longer use our one-sun system as a model for how stars are born.

Orbiting stars reveal location of black hole (
Orbiting stars reveal location of black hole (

But it was her enduring fascination with black holes that captured her imagination when she joined the UCLA faculty in 1994. Black holes are the ultra-dense remains of once-immense stars, so massive that even light cannot escape the pull of their gravity. Although we cannot "see" a black hole, we can see its effect on neighboring stars: the greater its mass, the faster the stars careen around it.

Attracted to the debate about what lies at the center of our galaxy, and with access to the largest telescopes in the world—the Keck telescopes in Hawaii—Ghez and her team at UCLA turned their attention and equipment 25-thousand light years away to the very center of the Milky Way. Over the last ten years, her team, the UCLA Galactic Center Group, has been collecting and publishing data that strongly suggests that our galaxy has at its core a gargantuan black hole, three million times more massive than the Sun.

A clearer look at the galaxy's center. (
A clearer look at the galaxy's center. (

Using "adaptive optics," a technology that literally deforms the telescope’s mirror to counteract fluctuations in the atmosphere, Ghez and her team were able to produce images of the center of the galaxy that were ten to 30 times clearer than had been formerly possible. The above image was taken using infrared light—waves of light just longer than the human eye can see, 2.2 millionths of a meter long. The images were so clear that astronomers could actually make out individual stars behind the dust at our galaxy’s core. These stars were moving so fast that a supermassive black hole was by far the most likely explanation.

But as Dr. Ghez points out, the discovery of this massive black hole produces more questions than answers. Do all galaxies have colossal black holes at their cores? And what surrounds the central black hole—a horde of smaller black holes? A halo of dark matter—objects which have mass but do not emit light? The answers to these questions could help scientists resolve some of the cosmological conundrums that captured Ghez’s imagination as a child.

As a researcher, Ghez relishes the freedom of choosing her subjects of study. When she designs an experiment, she starts with a question: What are the interesting problems of today and where can I make a contribution?

"If I come up with a good idea, I can go pursue it,” she says. “And that’s a luxury."

But it is the balance between her research and her teaching that makes her career so fulfilling. She feels a responsibility to encourage young women who are interested in physics to "go for it," getting research experiences and a solid basis in math and the general sciences. And she has found that the best way for her to reach a large number of people is to teach.

Research is a solitary job, a long-term effort which only her colleagues can fully appreciate. Although she gets to choose which questions she will tackle in her research, she may have no idea whether she has asked the right questions until she has worked on a problem for years. Teaching, on the other hand, is immediately gratifying. You know that day if you did a good job, says Ghez, based on the faces of your students.

Dr. Ghez discovered her passion for teaching around the same time she discovered that most stars are born in pairs, while still a doctoral student at Caltech. At the time, graduate students were not permitted to teach freshman physics courses. But she persuaded the administration that young physicists did not have enough female role models, and that her presence could encourage young women to pursue careers in astrophysics. Her concern for her students, her energy in teaching, and her accessibility won her students’ admiration, and they presented her with a Caltech teaching award that was usually reserved for faculty.

Andrea Ghez (Andrea Ghez)
Andrea Ghez (Andrea Ghez)

Now an award-winning astrophysics instructor at UCLA, Ghez says she still prefers to teach undergraduate courses.

"It’s where I can have the potential for making the greatest impact—showing that women can do the physical sciences."

To facilitate her students’ learning, Dr. Ghez includes cartoons with her exams and lectures, helping them to combat their physics-phobia by finding a connection to the material through a less threatening medium.

In addition to teaching, giving public lectures, attending international astrophysics conferences, visiting the Keck telescopes six times a year, analyzing computer data, writing proposals and publishing her results, Ghez is a full-time mother of two.

But high achievers beware: stress is part of the job, and those who are best suited for this career are good jugglers, who like to take on many responsibilities at once.

"You throw up way more balls than you can possibly catch," she says. "And the people who succeed know which balls to catch and which to let drop."

How does she cope with stress?

"I swim; that’s what keeps my head on straight."

In terms of research, Dr. Ghez has several balls in the air right now. One of them is to test the theory of general relativity by observing how celestial bodies act in the very strong gravity at the center of the galaxy. General relativity predicts that when a star encounters strong gravity, its orbit will disobey the laws of classical physics by "precessing:" with each revolution the orbital path will change slightly, like the design in a Spirograph. It would be a profound discovery indeed if Ghez’s team found that this prediction of general relativity did not hold up in the regime of strong gravity.

"That’s one of the exciting things about research," says Ghez. "You never really know in the long-term where you’ll go. New and exciting things keep cropping up."

Related Links

Home page of Dr. Andrea Ghez. - Dr. Ghez's official UCLA website.
- A description of current research topics with pictures and animations.
W.M. Keck Observatory - Learn more about the largest optical telescopes in the world.
- Webcast lecture by Andrea Ghez at the 95th UCLA Faculty Research Lecture. October 30, 2003.

Extra Info

This story was made possible by a grant from The Alfred P. Sloan Foundation.


Ghez, Andrea. "Homepage of Dr. Andrea Ghez." [Online] Available

Hornstein, Seth and Jessica Lu. "Home page for the UCLA Galactic Center Group." [Online] Available

UC Regents. "Center for Adaptive Optics." [Online] Available 2002-2003.

IPAC. "Cool Cosmos: Tutorial on Infrared Astronomy." [Online] Available

Nemiroff, Robert . "Virtual Tours to Black Holes and Neutron Stars." [Online] Available

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