Standing in my office 25 years ago was an unknown, newly minted astronomer with a half-smile on her face. She had come with an outrageous request—really a demand—that my team modify our exhaustively tested software to make one of our most important and in-demand scientific instruments do something it had never been designed for, and risk breaking it. All to carry out an experiment that was basically a waste of time and couldn’t be done—to prove that a massive black hole lurked at the center of our Milky Way.
My initial “no way” (perhaps I used a stronger expression) gradually gave way in the face of her cheerful but unwavering determination. It was my first encounter with a force of nature, Andrea Ghez, one of three winners of this year’s Nobel Prize in Physics, for her work on providing the conclusive experimental evidence of a supermassive black hole with the mass of four million suns residing at the center of the Milky Way galaxy.
That determination and the willingness to take calculated risks has always characterized Andrea. For 25 years she has focused almost exclusively on Sagittarius A*—the name of our own local supermassive black hole. It is remarkable that an entire field of study has grown up in the intervening quarter century, of searching for and finding evidence of these monsters thought to lie at the heart of every large galaxy. And Andrea is without question one of the great pioneers in this search.
Andrea’s co-prizewinner Reinhard Genzel has been involved in the same research from the outset—and it is the work of these two teams, each led by a formidable intellect and using two different observatories in two different hemispheres that has brought astronomy to this remarkable result—the confirmation of another of the predictions of Einstein’s more than century-old theory of general relativity.
As in so many fields of science, the competition has been intense, sometimes brutal, but out of this has been forged an unshakable result that has been tested and retested over a quarter century. And at the heart of the competition, two colleagues, great astronomers each, whose work has been as much defined by the science as by the availability of telescopes and instrumentation almost perfectly suited to this exact scientific endeavor.
Andrea did her work at the W.M. Keck Observatory’s twin telescopes on Maunakea, Hawai’i, in the calm and clear air almost 14,000 feet above the Pacific Ocean. She started using the very first instrument commissioned on Keck Observatory’s Near Infrared Camera (NIRC), now gracing the lobby at our headquarters. NIRC was never designed to do what Andrea needed—an ultrafast readout of images and then a restacking of the result to remove the effects of the atmosphere’s turbulence. But she was not to be denied—and we made the changes. And it worked! It was supremely hard and time-consuming to make sense of the data, but Andrea persisted.
Out of that effort came the first evidence—not just hints—of stars orbiting the black hole. It was