Most powerful atom smasher restarts

Scientists have restarted the world's most powerful atom-smasher overnight, the European Organisation for Nuclear Research (CERN) said yesterday, as they launch a new bid to uncover the secrets of the universe.

"The LHC is on its way again. First beam of 2010 circulated in each direction by 04.10 CET (0310 GMT)," said CERN in a tweet on its website yesterday.

The €3.9 billion Large Hadron Collider (LHC) was shut down in December to prepare it for collisions at unfathomed energy levels. It was run for a few weeks after being successfully revived from a 14-month breakdown.

The particle collider - inside a 27-kilometre tunnel straddling the Franco-Swiss border near Geneva - is aimed at understanding the origins of the universe by recreating the conditions that followed the Big Bang.

In the weeks before the technical shutdown in December, the collider achieved over a million particle collisions and accelerated proton beams to energy levels never reached before, according to CERN.

Collisions reached a world record energy level of 2.36 teraelectronvolts (TeV), already allowing scientists to gather data.

But CERN now wants to reach 7 TeV to try to recreate conditions close to the Big Bang, and run it at those levels for 18 to 24 months.

Subsequently the scientists aim to reach the LHC's design energy of 14 TeV, but only following another long technical shutdown in the second half of 2011.