London : 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.
