Meet Andrea Ghez: The puzzle-loving child who grew up to discover the Milky Way’s supermassive black hole |

Image: Left/Nobel Prize Org/Right/Canva

She was always fascinated by mathematics, logic puzzles and the thrill of solving difficult problems while Andrea Ghez was growing up in Chicago. What began as a curiosity about how things worked eventually led her to ask one of astronomy’s biggest questions: what lies at the centre of our galaxy? Unknown to the fact that decades later, her pioneering observations would provide some of the strongest evidence yet for the existence of a supermassive black hole at the heart of the Milky Way. In 2020, Ghez became one of the recipients of the Nobel Prize in Physics for her revolutionary work tracking stars orbiting an invisible yet extraordinarily massive object known as Sagittarius A*. Her journey from a puzzle-loving schoolgirl to one of the world’s most influential astronomers demonstrates how persistence, curiosity and scientific rigour can transform our understanding of the universe.

The scientific breakthrough that revealed a supermassive black hole in the Milky Way

Andrea Ghez, a professor of physics and astronomy at the University of California, Los Angeles (UCLA), spent more than two decades studying the crowded region surrounding Sagittarius A*, the compact radio source located at the centre of the Milky Way.Using the powerful telescopes at the W. M. Keck Observatory in Hawaii and advanced adaptive optics technology, Ghez and her team tracked the motions of individual stars orbiting an unseen object. Their measurements showed that these stars were moving at extraordinary speeds under the influence of an immense gravitational force.The Nobel Committee stated:“The discoveries of one of the heaviest and most exotic objects known, a supermassive black hole, are the result of the laureates’ groundbreaking work.”By observing stellar orbits over many years, Ghez demonstrated that nearly four million times the mass of the Sun is concentrated within a remarkably small region of space. The most convincing explanation is a supermassive black hole.In an interview with the Nobel Prize organisation:“Andrea Ghez and Reinhard Genzel led a group of astronomers that, since the beginning of the 1990s, has focused on a region called Sagittarius A* at the centre of our galaxy.”“As a scientist, make sure students become critical thinkers,” says Ghez. Their observations transformed a long-standing theoretical possibility into compelling observational evidence.

Andrea Ghez’s Nobel Prize journey and her message for future scientists

In 2020, Andrea Ghez shared the Nobel Prize in Physics with Reinhard Genzel, while the other half was awarded to Roger Penrose for his theoretical work demonstrating that black holes are a direct consequence of Einstein’s general theory of relativity.Reflecting on her scientific journey, Ghez has often highlighted the importance of curiosity and perseverance. In her Nobel Prize interview, she remarked:“I learned that you can do anything you want.”She has also spoken openly about overcoming barriers in a field historically dominated by men, encouraging young people, particularly girls, to pursue careers in science and mathematics.In her Nobel lecture, Ghez explained that the quest to understand the Galactic Centre required scientists to push technological boundaries, developing new methods to see through Earth’s atmospheric distortions and achieve unprecedented precision.Today, her work continues to influence modern astrophysics, helping researchers investigate black holes, galaxy formation and the fundamental laws governing the cosmos. What began with a childhood love of puzzles ultimately led to one of the most important astronomical discoveries of the modern era.

Why Andrea Ghez’s discovery changed our understanding of the universe

The significance of Ghez’s work extends far beyond the Milky Way. Supermassive black holes are now believed to exist at the centres of most large galaxies, influencing their growth, structure and evolution.By proving that an invisible object of immense mass occupies the centre of our own galaxy, Ghez helped establish black holes as central components of cosmic architecture rather than theoretical curiosities.As the Nobel Prize organisation noted:“A supermassive black hole is the only currently known explanation.”Her research continues to serve as a foundation for new discoveries, inspiring future generations to explore some of the universe’s deepest mysteries.