The Globe and Mail Cosmic oddity casts doubt on theory of universe
By�DAN FALK UPDATED AT 2:50 PM EST Saturday, Jan 29, 2005 A new analysis of the "echo" of the Big Bang has left cosmologists scratching their heads and could throw a monkey wrench into efforts to understand how the universe began. U.S. and European scientists analyzed the distribution of "hot" and "cold" regions -- areas that are putting out greater or less amounts of energy than the average -- of the cosmic microwave background radiation (the so-called echo). What they found was unexpected: an apparent correlation between those hot and cold spots and the orientation and motion of our solar system. "All of this is mysterious," says Glenn Starkman, a Canadian physicist based at Case Western Reserve University in Cleveland and one of the authors of a recent paper in Physical Review Letters that outlined the finding. "And the strange thing is, the more you delve into it, the more mysteries you find." The study, by Case Western scientists and the European Centre for Nuclear Research in Geneva, is based on data from the WMAP satellite, the NASA spacecraft that began mapping the cosmic microwave background (CMB) radiation in fine detail in 2001. The observed correlation is troubling on several fronts. First of all, there is no reason to believe that the finding reflects any physical connection between our local astronomical neighbourhood and the universe at large. As Dr. Starkman puts it: "None of us believe that the universe knows about the solar system, or that the solar system knows about the universe." Far more plausible, he says, is that something within our solar system is producing or absorbing microwaves. That means that anyone doing cosmology would have to take into account such "local" contamination. (The correlation involves the largest-scale fluctuations of the CMB radiation. If some of those fluctuations are a local rather than a cosmological phenomenon, it would mean that the truly cosmological large-scale fluctuations are even less intense than previously thought.) There is, however, another possibility: The patterns seen by Dr. Starkman and his colleagues might simply be a fluke -- an accidental alignment between the solar system and patterns in the CMB radiation. If the correlation is real, however, it could cast doubt on the popular "inflation" model of the early universe. That model, which builds on the well-established Big Bang theory, says the universe underwent a period of incredibly rapid, exponential growth in the first split-second of its existence. One of its predictions is that the universe should be nearly perfectly "smooth," that the CMB fluctuations should be equally intense at all scales. An analogy with a musical instrument can be helpful: If you hit a drum, you hear many tones at the same time -- a primary tone as well as many overtones, or "harmonics." The inflation model predicts that all the overtones in the CMB should be equally intense, but instead "we're missing the bass," Dr. Starkman says. "And what bass there is seems to be not generated by the universe, but by something local." Other physicists are responding with caution to the finding. "There is no way to judge the real significance of such a result," says Charles Bennett of NASA's Goddard Space Flight Center in Greenbelt, Md., the leader of the WMAP team. It all depends on how we perceive "chance," and how we evaluate probabilities, Dr. Bennett says. The alignments seen in the CMB may seem unlikely, he says, but that doesn't necessarily mean that they require new physics to explain them. He points out that "improbable things happen frequently because there are lots of opportunities for them to occur." In other words, he says, the newly discovered CMB correlations are most likely the product of chance. Dan Falk is a science journalist based in Toronto. � �� 2005 Bell Globemedia Publishing Inc. All Rights Reserved.
