My Top 10 Science Stories of 2005 – #2

COSMOLOGY

Can a Local Pancake Defeat the Axis of Evil?

By Davide Castelvecchi
In the past few years, astronomers and physicists have finally nailed down some of the basics of the universe. They have figured out its age, at about 14 billion years; they have determined how it started, apparently coming out of a speck of empty space, in a ridiculously brief age of exponential growth called inflation; and they have calculated with great confidence that they don’t have a clue what 95 percent of the universe is made of. That is real progress: at least, now scientists know exactly how much they don’t know.Much of the new age of precision cosmology is founded on the shots of the baby universe that came from a NASA orbiting microwave telescope called WMAP, whose 2003 results were hailed breakthrough of the year by Science magazine. But two problems with the standard cosmology emerged later, in 2004 (see also New Scientist, 11 December 2004). I didn’t pay too much attention to these claims until I read an article in the August issue of Scientific American by Glenn Starkman and Dominik Schwarz, who coauthored some of the new research. Scientists study the WMAP data by comparing the cosmic microwaves coming from different directions and analyzing them mathematically the same way a sound wave is decomposed in harmonics.

The article explained that, first, the lower harmonics in the WMAP data seem incompatible with the inflation model of the big bang, and second, that the microwaves picked up by WMAP seem to be skewed in the direction of the Virgo constellation — a perplexing alignment that was dubbed “axis of evil.” Some experts suggested the discrepancies could come from some hidden bias in WMAP’s instruments, while others remained perplexed.

The news came as a shock to me, especially since in my article in the December 2004 issue of Symmetry I had reviewed what experts thought of inflation on its twenty-fifth birthday, and I had assured the reader that everything was fine.

In October, Fermilab physicist Chris Vale proposed a solution, at least for one of the problems. In a paper improbably entitled “Local Pancake Defeats Axis of Evil,” he described his calculations that the Shapley supercluster, a huge concentration of galaxies about 450 million light years away, could be responsible for skewing the microwave background by curving spacetime, according to Einstein’s general relativity.

According to New Scientist, experts take Vale’s paper very seriously, although apparently his solution raises new problems. Meanwhile, the long-awaited new release of data by the WMAP team still hasn’t happened — something to look forward to in 2006?Looks like there will be plenty more juicy cosmology stories to cover in the future.

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