US: The two Americans behind the satellite experiment that measured the leftover energy from the creation of the universe have won the 2006 Nobel Prize in Physics.
The Royal Swedish Academy of Sciences awarded the 10 million Swedish crown (€1.14 million) prize to John Mather (60), of the Nasa Goddard Space Flight Centre in Maryland and George Smoot (61), an astrophysicist at Lawrence Berkeley National Laboratory and a physics professor at the University of California, Berkeley
They spearheaded Nasa's COBE (Cosmic Background Explorer) satellite programme. It provided the first hard evidence for the "big bang" theory, which describes the creation of the universe.
The satellite took very precise measurements of the energy left behind by the big bang explosion that created space and time.
The explosion produced temperatures reaching millions of degrees, but now the remnant cosmic microwave background radiation (CMB) measures no more than 2.7 degrees above absolute zero, the coldest possible.
Theoretical physicists predicted the CMB decades ago and its signal was actually picked up by accident and heard by Bell Laboratory scientists in 1965 during experiments on sensitive antenna systems.
Mather's and Smoot's work finally provided large volumes of highly accurate experimental data on the CMB. It provided solid evidence for the big bang but also allowed scientists to look backwards in time to what the universe looked like 300,000 years after the explosion.
Mather co-ordinated the entire COBE satellite programme, while Smoot had the main responsibility for measuring small temperature variations in radiation, the academy said.
"It was the seminal experiment. It converted cosmology from a theoretical to an experimental science," said Prof Niall Ó Murchadha, a gravitational physicist in University College Cork (UCC). "They were actually able to look way, way back to the foundations of the universe."
"The discovery of the microwave background was the most important discovery in astrophysics in the last century," said UCD professor of experimental physics Prof David Fegan.
"What they were able to do is look back as far as it is possible to look at the early universe," said UCC astrophysicist Dr Paul Callanan. - (Additional reporting Reuters)