In an unusual logjam of contradictory claims, a revolutionary new model of the universe, as a soccer ball, arrives on astronomers' desks this morning at least slightly deflated.
In a paper being published today in the journal Nature, Dr. Jeffrey Weeks, an independent mathematician in Canton, N.Y., and his colleagues suggest, based on analysis of maps of the Big Bang, that space is a kind of 12-sided hall of mirrors, in which the illusion of infinity is created by looking out and seeing multiple copies of the same stars.
If the model is correct, Dr. Weeks said, it would rule out a popular theory of the Big Bang that asserts that our own observable universe is just a bubble among others in a realm of vastly larger extent. ''It means we can just about see the whole universe now,'' Dr. Weeks said.
But other astronomers, including a group led by Dr. David Spergel of Princeton, said a continuing analysis of the same data had probably already ruled out the soccer ball universe. They promised to post their results soon on the physics Web site arXiv.org/list/astro-ph.
''Weeks and friends are making a dramatic claim, perhaps one of the biggest science stories of the century,'' said Dr. Neil Cornish, a physicist at Montana State University, ''but extraordinary claims require extraordinary support.''
For now, the two groups, who have been in intense communication the last few days, disagree on whether the soccer ball universe has been refuted. What is amazing about this debate, they all agree, is that it will actually be settled soon, underscoring the power of modern data to resolve issues that were once considered almost metaphysical.
''This is what got Giordano Bruno burned at the stake,'' said Dr. Max Tegmark, a cosmologist at the University of Pennsylvania. ''Is space infinite or not?''
In Nature, Dr. Weeks and his colleagues write: ''Since antiquity, humans have wondered whether our universe is finite or infinite. Now, after more than two millennia of speculation, observational data might finally settle this ancient question.'' The other authors are Dr. Jean-Pierre Luminet of Paris Observatory; Dr. Alain Riazueleo of the French atomic energy center CEA, in Saclay, France; Dr. Roland Lehoucq of the Paris Observatory and CEA; and Dr. Jean-Phillippe Uzan of the University of Paris.
The evidence for and against a finite universe resides in a radio map of the baby universe produced last February by a NASA satellite, the Wilkinson Microwave Anisotropy Probe. It shows that 400,000 years after the Big Bang, the event in which space and time emerged, the universe was laced with faint waves and ripples, which are the origin of modern galaxies and other cosmic structures. In an infinite universe, according to theory, waves of all size should appear in the sky, but in the Wilkinson data there was a cutoff: no waves larger than about 60 degrees across appeared in the sky.
If the universe were a musical instrument, it would be inexplicably missing its low notes, perhaps, some cosmologists have suggested, because it is too small to play them. The universe is finite rather than infinite, they speculate. Like a violin that cannot produce deep cello notes, the universe cannot produce waves larger than itself.
In such a universe, if you went far enough in one direction, you would find yourself back where you started, on the other side of the universe, like a cursor disappearing off the left side of a screen and reappearing on the right.
One simple example of this is a torus, or a bagel shape, which is what you get when you wrap the left and right and top and bottom sides of the screen around so that they meet.
In the Nature paper, Dr. Weeks and his colleagues propose that three-dimensional space has 12 sides, like a soccer ball, or more technically a dodecahedron. This model would fit with the cutoff of large waves observed in the Wilkinson satellite data. Each face is ''glued'' to its opposite number. (Don't try this at home.) A spaceship crossing one face or panel of the soccer ball would enter the other side of the ball. After traveling 74 billion light-years it would find itself back where it had started.
