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The observations were moved to the head of the Hubble schedule, and by July, Freedman was looking at a pattern on her computer screen that was as familiar as the face of an old friend. "Boom!" she remembers. "All of a sudden there was this glorious Cepheid light curve, as beautiful as any that have ever been measured." By the end of the observing run, Freedman and her colleagues found 19 more, enough to peg M100's distance at some 56 million light-years from Earth.
That still isn't far enough out to give a direct measure of the Hubble-the cosmic rate of expansion. But M100 is part of a huge group of galaxies known as the Virgo cluster. The M100 calculation gave the astronomers the distance to Virgo, and they used that number in turn to estimate the distance to the Coma cluster of galaxies, about five times as far away. Coma, finally, is far enough out that it's a reliable indicator of the Hubble Constant. Based on Freedman's analysis, the Constant comes in at 80, indicating a universe between 8 billion and 12 billion years old.
While most astronomers take these numbers very seriously-along with the cosmic paradox they imply-Allan Sandage, Freedman's grumpy colleague down the hall, is having none of it. He doesn't quibble with her measurement of the distance to M100, but insists that the analysis breaks down after that. Like most astronomers, Sandage has his favorite method of gauging the relative distance of galaxies. He finds a type of supernova-an exploding star-and compares supernova brightnesses from one galaxy to another. He claims, as he has done for more than 20 years, that the Hubble Constant is lower, which means the age of the universe goes up considerably. Says Oklahoma's David Branch, his close collaborator: "We're very happy to be in this controversy because we think we're right."
But most astronomers don't-partly because just about everyone else gets different results, partly because they suspect Sandage is guilty of a cardinal sin of science: having a preferred answer in mind before making observations.
Freedman is the first to admit her team's age figures could be off 20% in either direction. The reason: no one knows whether M100 lies inside the Virgo cluster or whether it is more in the foreground or background. Astronomers have to check out other galaxies in the area before they are sure that M100 fairly measures the distance of the cluster as a whole. They're also checking galaxies outside Virgo, and while Freedman won't say what they have found so far, she told TIME that the results are "consistent" with the preliminary figures.
If she's right and Sandage is wrong, as many cosmic handicappers are betting, then the age crisis won't go away without some fundamental change in the way astronomers understand the cosmos. That means at least some scientists will have to give up their cherished beliefs about how stars work or how the universe is organized or what it's made of-or maybe even all of the above.