Have Traces of Cosmic Strings Been Found? Scientists Says "Yes"

A controversial study indicates that there are traces of vast cosmic strings left over in radiation from the early universe. If indeed confirmed to be real, these cosmic strings would offer an unprecedented window into the extreme physics of origins of the universe.

The idea is that snags in the fabric of space may have developed a fraction of a second after the universe's birth. This would have likely occurred at the end of the period called inflation when the universe was rapidly expanding.

These “snags” are thought to be shaped like very slender strings, with a thickness much less than the width of an atom but with lengths that can be measured in light years. They would also be incredibly heavy. A section just a kilometer long would potentially have as much mass as the entire Earth.

Now a team of scientists says there is some valid evidence that these elusive and exotic strings really do exist. They claim that traces of cosmic strings can be detected in the afterglow of the big bang. Neil Bevis of Imperial College London and his team used the Wilkinson Microwave Anisotropy Probe (WMAP) satellite to observe radiation called the cosmic microwave background.

This radiation is slightly patchy because of the distribution of the glowing matter that produced it. If present, cosmic strings should attract matter with their gravity, slightly altering the way it is distributed in the early universe.

The team of scientists used computers to simulate how the microwave background should look with and without cosmic strings, and compared the results to the WMAP observations. They found a better agreement when cosmic strings were included.

"This is an exciting result," says Mark Hindmarsh, of the University of Sussex, Brighton, UK, one of the study's authors. "Cosmic strings are relics of the very early universe, and signposts that would help construct a theory of all forces and particles."

But there is a 5% chance that the correlation would be produced simply by random noise, and such flukes should be expected from time to time because so many studies of WMAP data are published each year, says Charles Bennett, the chief scientist for the WMAP mission.

Future observations should clarify things. The Planck satellite, due to launch in 2008, will make even more sensitive measurements of the microwave background than WMAP, and could turn up better evidence for cosmic strings.

Posted by Rebecca Sato.