Dark energy 99.996pc real, scientists claim

London, September 13 (ANI): An Anglo-German team of astronomers have claimed that dark energy, the mysterious cosmic force thought to be the fuel behind the accelerating expansion of the universe, is real.

After a two-year study, scientists at the University of Portsmouth in the United Kingdom and LMU University Munich in Germany have concluded that the likelihood of dark energy's existence stands at 99.996 percent.

"Dark energy is one of the great scientific mysteries of our time, so it isn't surprising that so many researchers question its existence," the Daily Mail quoted Bob Nichol, a member of the Portsmouth team involved in the research, as saying.

"But with our new work, we're more confident than ever that this exotic component of the universe is real - even if we still have no idea what it consists of," he said.

Dark energy is thought to make up 73 percent of the cosmos, while the slightly less mysterious dark matter comprises the remaining 23 percent.

One of the strongest pieces of evidence for dark energy is in the so-called Integrated Sachs Wolfe effect.

In 1967, Rainer Sachs and Arthur Wolfe theorized that light from the radiation from the heat left over from the Big Bang, would become slightly more blue as it passed through the gravitational fields of lumps of matter in the universe, an effect known as gravitational redshift.

The existence of dark energy would cause light from this residual radiation to gain energy as it travels through large lumps of mass.

In 1996, astronomers Robert Crittenden and Neil Turok suggested overlaying a map of the local universe on the picture of the residual cosmic radiation could provide clues about where to look for the effect. In 2003, it was spotted, albeit weakly.

It was seen as supporting evidence for dark energy and hailed as the 'Discovery of the Year' in Science magazine.

But some scientists argued it could have been caused by cosmic dust and questioned the discovery.

The Anglo-German team, led by Crittenden and Tommaso Giannantonio, re-examined all the arguments against the detection and have improved the maps used in the original work.

They concluded that dark energy is almost certainly responsible for the hotter parts of the cosmic microwave background.

"We have methodically addressed all of these issues and concluded none of them can explain the observations we see. In the end, the only remaining explanation is dark energy - if it walks like a duck and quacks like a duck, it's probably a duck," Nichol told a foreign news agency.

Radio telescopes like the huge Square Kilometre Array that will be sited in remote areas in South Africa and Australia, should improve the tricky process of measuring distances in the universe and give more definitive data, he said.

However, he admitted that they still have no idea what it consists of.

Their study was published in the academic journal Monthly Notices of the Royal Astronomical Society. (ANI)