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While the lack of cosmic low notes is suggestive, cosmologists say there is a definitive test of finite universes in the Wilkinson map. When the cosmic radiation intersects the edges of the universe, it would make identical circles, like a balloon squashed in a box, on opposite sides of the sky. In the case of a bagel, there would be two circles in the map, on opposite sides of the sky. In the case of Dr. Weeks's dodecahedron, there would be six pairs of circles, each about 35 degrees in diameter.
''This is a much higher bar to clear,'' Dr. Cornish said.
Dr. Tegmark said: ''What's nice is it's so testable. It's the truth or it's dead. The data is even out there, on the Internet. It's just a question of sifting through it.''
But so far the circles have not showed up.
Earlier this year, Dr. Tegmark and his wife and colleague Dr. Angelica Oliveira-Costa, Dr. Mattias Zaldarriago, of Harvard, and Dr. Andrew Hamilton of the University of Colorado, searched the Wilkinson data for oppositely matched circles. The results, they said, ruled out the possibility that the universe was shaped like a bagel, no doubt disappointing New Yorkers who would like to have imagined a cosmic connection with their breakfast.
Dr. Tegmark said that the results also ruled out Dr. Weeks's dodecahedron. ''We ought to have seen those circles in our study,'' he said.
Meanwhile, a more thorough analysis of the data, looking for all possible circles, has been undertaken by Dr. Spergel, who was part of the original Wilkinson team, Dr. Cornish, and Dr. Glenn Starkman of Case Western Reserve University in Cleveland. The study, about two-thirds complete, had already eliminated many simple models of so-called ''small universes,'' including a dodecahedron when the Nature paper hit their desks last week, Dr. Spergel said.
''No soccer ball, no doughnuts, no bagels,'' he said.
But Dr. Weeks said there were potential gaps in the circle search methods. For one thing, if the dodecahedron were slightly larger, he said, the circles would be smaller and would not show up in Dr. Spergel's search. But until all the papers are posted on the archive or published where everybody can read them, these claims cannot be evaluated.
Dr. Weeks said that astronomers from both teams would join this fall to test the circle search, using simulated data. If the models are false, they could be ruled out as early as November, he said.
Dr. Cornish said that, although it was the scientific community that would ultimately decide, his team was confident of its results. ''I don't see any wiggle room,'' he said.
But because it is such a ''truly spectacular claim,'' he said, they are planning in the next few days to run a special test focused on the particular model. The test could detect very small circles. ''We can push it to where there's no chance,'' Dr. Cornish said.
The prospects for the finite universe, he added, look bleak.
The stakes for cosmology, should the soccer ball or some other variety of small universe prevail, are not small at all. A small universe, everybody agrees, would present severe problems for the prevailing theory of the Big Bang, known as inflation, which posits that the cosmos underwent a burst of hyperexpansion in its first moments.
Moreover, Dr. Weeks said, a small universe would eliminate one popular variant of the theory known as eternal inflation, in which bubble universes give rise to one another endlessly in what some cosmologists call a ''multiverse.''
''This puts the whole universe in view,'' he explained. ''It wouldn't rule out other universes. There could be others. They would be totally unrelated, without any contact between them.''
Chart: ''Giving Shape to the Universe'' Radiation left over from the Big Bang, right, seen by the WMAP satellite in February, depicts the early universe. Scientists expect the data to determine whether the universe is finite or infinite. Which shape best predicts the patterns that were seen by the satellite? Some computations suggest it is a dodecahedron, a 12-sided object. In this scenario of a finite universe: 1. Space travelers leave the dodecahedron across one face. 2. They would return from the opposite face. The observer's line of sight wraps around the universe in the same way, producing the illusion of a cosmos repeating along a dodecahedral latticework, at right, like a house of mirrors. (Source by Dr. Jeffrey Weeks)
