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Marcy didn't rest on his euphoria. He and Butler went into high gear, determined to be at least the second team to find planets around a sunlike star. They begged telescope time from their colleagues and borrowed more than $100,000 worth of computer equipment to crunch gigabytes' worth of data from observations stretching back over eight years. "We knew," says Butler, "that we could get scooped again and again by the Swiss team."
After two months, they had analyzed 60 of the 120 stars in their survey. On the morning of Dec. 30, Butler went to the office to check on the computer's progress. "When I saw the data come up, I was completely blown away," he says. It was the telltale signature of the object orbiting around 70 Virginis. Recalls Butler: "It knocked me off the chair." His colleagues at the American Astronomical Society's winter meeting in San Antonio, Texas, where Marcy and Butler announced their findings two weeks ago, were no less excited. "What we are seeing," said Robert Brown, an astronomer with the Space Telescope Science Institute, after Marcy sat down, "is the culmination of intellectual history that began with Copernicus 500 years ago."
It is also a beginning of sorts. Faced with the existence of these planets, astronomers must now revise their theories to fit the new facts. To begin with, theorists have to scramble to explain how the 51 Pegasi planet could have formed and survived intact so close to its parent star. The planet around 70 Virginis is also problematic: its orbit is egg-shaped rather than circular, which suggests to some astronomers that it formed more like a star than like a planet. Indeed, many experts think it is technically a brown dwarf--a star that never got big enough to ignite--rather than a planet. Only the third object matches what astronomers expected. Says Brown cautiously: "I can't say for certain that it is a planet. But so far, it looks like a planet, it walks like a planet, it quacks like one."
What the data may be saying is simply that the dividing line between stars and planets may be less distinct than astronomers had believed. "Everything found so far poses challenging questions for planetary formation theory," says astronomer Robert Stefanik, of the Harvard-Smithsonian Center for Astrophysics. That was underscored last week when, after weeks of government shutdown, results were released from a NASA experiment much closer to home. The probe's plunge from the Galileo spacecraft into Jupiter's atmosphere showed that the planet has higher winds, less lightning, less water, helium and neon, and--at the point of impact at least--fewer clouds than the experts had been expecting.
More surprises are almost certain to follow if astronomers find more and more planets circling other stars. But while finding new planets of any sort is terrifically exciting, says Alan Boss, an astronomer at the Carnegie Institution of Washington, "the Holy Grail is to find an extrasolar planet that is capable of supporting life."