'Big Bang' collider to re-start
Geneva - The world's largest scientific experiment will try to collide particles at the highest energy level so far from March 30, recreating conditions at the "Big Bang" birth of the universe 13.7 billion years ago, Cern said on Tuesday.
The Large Hadron Collider (LHC), centred in a 27km circular underground tunnel beneath the French-Swiss border, began circulating particles last November after being shut down in September 2008 because of over-heating.
Twin beams are currently circulating at 3.5 tera-electron volts (TeV), the highest energy ever achieved, and will accelerate in coming days, according to the European Organisation for Nuclear Research (Cern).
"The first attempt for collisions at 7TeV (3.5TeV per beam) is scheduled for March 30," it said in a statement.
"It may take hours or even days to get collisions," said Rolf Heuer, Cern's Director-General.
The multiple collisions at 7TeV will each create mini-Big Bangs, producing data that thousands of scientists will analyse for years to come.
"Just lining the beams up is a challenge in itself: it's a bit like firing needles across the Atlantic and getting them to collide half way," said Steve Myers, Cern's director for accelerators and technology.
Once the high-speed collisions are established, the plan is to run continuously for 18 - 24 months, with a short technical pause at the end of 2010, Cern said.
Dark matter, which scientists believe makes up 25% of the universe, but whose existence has never been proven, could be detected, officials said.
Astronomers and physicists say that only 5% of the universe is known currently, and that the invisible remainder consists of dark matter and dark energy, which make up some 25% and 70%, respectively.
"If we can detect and understand dark matter, our knowledge will expand to encompass 30% of the universe, a huge step forward," Heuer told a news conference earlier this month.