The Italian Almanac

a far galaxy as seen by HUB telescope

Italian Science - March 23

A small group of physicists are battling what they see as the cosmological equivalent to the bogeyman: an enormous dark force, that nobody has ever seen, driving galaxies apart. Conventional wisdom holds that the mysterious force, called "dark energy," may make up 70 percent of the universe, and could be the determining factor in whether it is eventually destroyed billions of years from now.

But Italian and American cosmologists are offering a controversial alternative to explain the accelerating expansion of the universe. They say it's not dark energy, but an overlooked after-effect of the "Big Bang" -- which cosmologists believe gave birth to the universe.

"No mysterious dark energy is required," said Antonio Riotto at Italy's National Nuclear Physics Institute in Padova. "If dark energy were the size that theories predict ... it would have prevented the existence of everything we know in our cosmos."

Albert Einstein once proposed a similar "cosmological constant," entering an anti-gravity factor into his general theory of relativity to offset gravity and create a balanced, static universe. When he later discovered that the universe was expanding, he called the cosmological constant his "greatest blunder," but dark energy revived the idea of an anti-gravity force.

"We think Einstein was right when he said he was wrong," said Edward W. Kolb of the U.S. Department of Energy's Fermi National Accelerator Laboratory. Kolb and the Italians say the universe's accelerating expansion is the result of long ripples in the fabric of space-time created by the big bang, during an "inflation" phase of rapid expansion of the universe, which have not been properly accounted for since they stretch beyond the observable universe.

Not all cosmologists are buying into the theory, which will be poured-over following its submission this month to the journal Physical Review Letters. "Their paper is going to get enormous scrutiny, and my own guess is that in the end, they'll be wrong," said cosmologist Michael Turner at the University of Chicago, who coined the term "dark energy," and published a paper with Kolb in 1990.

"The next generations of experiments that are done should be able to distinguish or tell us which if any of the ideas are correct. Whether it's dark energy or our proposal," said Kolb.