Now ready to roll: Image shows the magnetic core being loaded into the Compact Muon Solenoid (CMS) detector of the LHC during construction.

Credit: AFP

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11,000 laps per second

LHC project leader Lyn Evans, who has been working on the collider for 14 years, said he felt a wave of relief after the protons had completed their first lap so smoothly. "It's a machine of enormous complexity and things can go wrong at any time," he said.

Messages of congratulations flooded in from CERN's partners and rivals, including the legendary Fermilab particle physics lab near Chicago.

The LHC took nearly 20 years to complete and at 3.76 billion euros, (US$ 5.46 billion) is one of the costliest and most complex scientific experiments ever attempted.

When all is ready, at full speed the LHC will whizz the two beams around the tunnel at up to 11,000 laps per second before steering them into collisions into four chambers whose walls are swathed with detectors.

The first collisions are likely to start in several weeks, but only next year will the LHC be cranked up to its full capacity of 14 teraelectronvolts – a massive amount of energy that will briefly generate temperatures 100,000 times hotter than the Sun. It will be seven times the record held by Fermilab.

For all of humanity

Over the 10 to 15 years in which will the LHC will operate, masses of data will spew from these collisions and will be scrutinised by physicists around the world.

"It's about acquiring knowledge for humanity about the behaviour of fundamental matter," said LHC physicist Daniel Denegri. "We expect to make discoveries that could be rather spectacular."

"Basic knowledge is part of the heritage of humanity," added co-worker Daniel Froidevaux.

The holy grail will be finding a theorised sub-atomic component called the Higgs boson, which would explain how particles acquire mass. Believed to be ubiquitous – yet also frustratingly elusive until now – the Higgs has been dubbed the "God particle."

French President Nicolas Sarkozy, whose nation holds the European Union presidency, hailed Wednesday's start-up test as "a very big success for Europe."

"The spin-offs from this unprecedented scientific investment in the history of humanity are essential not only to deepen the intimate knowledge of the universe but also for direct applications in such varied areas as intensive calculations or even medicine," he said in a statement.