Andrea Ghez

1965–

Andrea Ghez tracks the orbits of stars near the Galactic Centre. Their movements reveal an enormous mass concentrated in a very small region associated with Sagittarius A*.

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A life of research

Born in New York, she studied at the Massachusetts Institute of Technology and the California Institute of Technology. At the University of California Los Angeles, she developed an observing programme focused on our galaxy's centre.

Her team uses the Keck telescopes and infrared imaging to see through obscuring dust. High-resolution techniques, including adaptive optics, help reduce the blurring produced by Earth's atmosphere.

Understanding the contribution

By observing the same stars over many years, the researchers reconstruct their trajectories. The speeds and shapes of their orbits allow the central mass to be calculated using the laws of gravity.

The results indicate approximately four million solar masses packed into a very compact volume. Together with independent work by Reinhard Genzel's team, they provide major evidence for a supermassive black hole at the centre of the Milky Way.

What this work changed

The 2020 Nobel Prize in Physics recognised this observational achievement. It shows how the motion of luminous objects can reveal a central object that is not itself directly visible.

Andrea Ghez

A life of research

Understanding the contribution

What this work changed

Sources and references