Moreover, observations of the cosmic background radiation enabled Weeks and his colleagues to posit possible shapes for the universe to explain its fluctuating density. The researchers could then test their models through mathematical proofs against the microwave data gathered by the WMAP satellite.
Among cosmologists, three broad categories vie as the most likely shapes to fit the cosmos: flat, negatively curved (saddle-shaped), and positively curved (spherical) space.
But Weeks said the discovery of dark energy in 1998, a little-understood force found in the vacuum of space, make models for negatively curved space more difficult to reconcile with scientific observations. Meanwhile the shape of flat universe models, Weeks said, imperfectly fit the mathematical proofs derived from WMAP cosmic background radiation recordings.
So Weeks said he started with the simplest model of a finite space, a torus.
(To picture a torus, roll up the sides of a piece of paper to create a cylinder. Starting over, roll the paper top to bottom to create a new cylinder. Now imagine rolling both ends simultaneously, but instead of using papertwo-dimensional spacestart with the rectangular space of your office or living roomthree dimensional space.)
"When you actually go and do the computation and you say, what sort of microwave sky do you expect to see in a torus universe, it doesn't match very well," said Weeks.
"But the good news then is that if you start with a dodecahedral block of space and again hook up on the sides, then it matches quite well."
In other words, taking the density fluctuations in cosmic background radiation recorded by WMAP, the math adds up if the universe is finite and shaped like a dodecahedron.
Weeks cautions that his team's model of a finite, dodecahedral-shaped universe, while promising, is hardly a proven theory. "There's more work to be done, he said. "It could be affirmed, or it could be refuted."
A description of their research appears tomorrow in the science journal Nature.
In an accompanying perspective article, George F. R. Ellis, a mathematician at the University of Cape Town, South Africa, writes that the researchers' cosmic map "accounts for the WMAP data better than do standard models," he wrote.
"Can this proposal be confirmed? Yes indeed," Ellis wrote, noting that future observations from WMAP's successor, a European satellite to be launched in 2007 even more accurate than its NASA counterpart, will provide key observations on cosmic background radiation that could confirm or disprove Weeks' theory.
Ellis concluded: "The WMAP data, as interpreted by [Weeks and colleagues], suggest that we might indeed live in such a small closed universe."
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