GENEVA, September 10 – Particle physicists fired up the world’s biggest atom-smasher on Wednesday in a mission to answer some of the most perplexing questions about the nature of the Universe.
Built in a tunnel 100 metres (325 feet) below ground in a complex straddling the French-Swiss border, the Large Hadron Collider (LHC) is designed to accelerate sub-atomic particles to nearly the speed of light and then smash them together.
The collisions will briefly stoke temperatures 100,000 times hotter than the Sun, fleetingly replicating conditions which prevailed in split-seconds after the "Big Bang" that created the Universe 13.7 billion years ago.
In this seething primordial soup, novel particles may lurk.
Discovering them could resolve mysteries clouding our understanding of how matter is constituted and came into being, scientists say.
"It’s about acquiring knowledge for humanity about the behaviour of fundamental matter," physicist Daniel Denegri told AFP.
"We expect to make discoveries that could be rather spectacular."
Shortly after 9:30 a.m. (0730 GMT), the first protons were injected into the 27-kilometre (16.9-mile) ring-shaped tunnel at the headquarters of the European Organisation for Nuclear Research (CERN).
It has required nearly two decades, six billion Swiss francs (3.76 billion euros, 5.46 billion dollars) and 5,000 scientists, engineers and technicians from nearly three dozen countries to bring the LHC to fruition.
Wednesday’s operation began a long and cautious commissioning process, testing equipment and procedures, before starting experiments a matter of weeks from now.
In the LHC control room, relieved scientists cheered and clapped when the first particles completed a maiden, clockwise lap around the ring. The protons’ progress had been slowed down to ensure that systems were working properly.
When all is ready, the LHC will whiz two parallel beams, one clockwise and the other anticlockwise, around the tunnel.
Superconducting magnets cooled close to absolute zero, the chill of deep space, will then steer the beams so that they converge inside four chambers whose walls are swathed with detectors.
"The way to think about it is like having cross-pointing machine-guns, firing bullets," said Denegri. "Some of the bullets will miss each other and others will hit."
When protons collide, subatomic wreckage from the smash-up will fly into the detectors, leaving a calling-card trace of their identity.
Over the 10-15 years in which will the LHC will operate, masses of data will spew from these collisions and will be closely scrutinised by universities and laboratories around the world.
The Holy Grail will be finding a particle, called the Higgs Boson after British physicist Peter Higgs, who devised the theory of its existence in 1964.
The "Higgs" would explain how particles acquire mass, and some particles are more massive than others.
The idea is that these particles exist in a sort of invisible background field. Other particles passing through the Higgs field would pick up mass, like feathers passing through thin treacle.
Another big challenge will be testing the theory of supersymmetry, which postulates that the members of the known bestiary of sub-atomic particles have related, but more massive, counterparts.
Such particles could explain the unsettling discovery of recent years that visible matter only accounts for some four percent of the Universe. Enigmatic phenomena called dark matter and dark energy account for the rest.
Before the start up, Internet-driven rumours said the LHC would create black holes or a nasty hypothetical particle called a strangelet that would gobble up the planet. CERN commissioned a panel to verify its safety calculations and France also carried out its own assessment.