Thirteen state-of-the-art telescopes stand on Mauna Kea, the tallest mountain in the Pacific basin, looming over the island of Hawaii. By day the view from the peak is of a rich blue black sky. By night, the pitch darkness is studded with starry diamonds. At nearly 14,000 feet, the mountain offers an untainted view of the heavens that is increasingly rare in a lit-up world, a view that makes an astronomer’s work a lot easier.  

Photograph by Amanda Friedman

Geoff Marcy (left) and Paul Butler are reflected in a mirror segment from the Keck I telescope, which they use to find extrasolar planets. “We’re lucky we don’t have any children,” says Marcy. “Our kids are the planets.”

Late on a Saturday night, Geoff Marcy and Paul Butler are hunched over computer monitors in an office 12,000 feet below the summit, in the nearby ranching town of Waimea. People turn in early here, but Marcy and Butler—who, in their 16 years of planet hunting, have found 61 of the 77 planets outside our solar system that are recognized by astronomers—call themselves vampires. From 7 p.m. to 6 a.m., with the help of graduate student Jason Wright, they preside over a series of workmanlike photo shoots. Again and again they point Keck I, the world’s largest telescope, at one of the stars on their hit list and shoot. They do this until they’ve captured the light of 100 or so stars that interest them. A spectrometer splits that light into its component colors from red to violet, generating a rainbow image so complex that it can be analyzed only by computer.

Extrasolar planets are too faint to be seen, even with Keck. So Marcy and Butler must infer their presence by studying how stars are affected by the gravitational tug of planets around them. Although a star may be thousands of times more massive, a smaller planet’s pull can cause it to wobble. Early in their careers, the duo spent seven years writing software that would let them nail down the wobble with accuracy. Now they can detect a wobble of a celestial body as slow as three meters per second, about the speed of a bicycle in motion.

The magic hour has just arrived when data from the previous night’s viewing start streaming back from Marcy’s computer in Berkeley and Butler’s machine in Washington, D.C. The computers have crunched the numbers overnight and plotted the data on graphs depicting the shape and period of each planet’s orbit. “This is a pretty one!” yells Marcy, 48, enthusiastic despite the dark circles under his eyes.

He turns to a visitor. “That’s a new planet, known only to the three of us in this room, and now you.” Butler, 43, a hulking man in a Hawaiian shirt, shorts, and sandals, looks over his shoulder and says, “Tell anyone and we’ll have to kill you.”

Marcy is small and chatty, Butler huge and less talkative. They grew up in Southern California, a few miles and years apart. Marcy’s parents gave him a map of the solar system and a telescope, which he used to plot the orbit of Saturn’s moon Titan when he was only 14. At the same age, Butler built his own eight-inch telescope; he was fascinated by the tales of what had happened to astronomers like Galileo, the first person to use a telescope to make astronomical observations, and Giordano Bruno, who dared to dream of multiple worlds and parallel universes. Galileo ended up under house arrest, and Bruno was burned at the stake. “Wow,” Butler remembers thinking, “this is wild, rock-and-roll stuff. The powers that be are threatened by it!”