Knock knock knocking on Heaven's door

Professor Peter Higgs is expecting to find proof of an all-pervading force. Photo / Reuters

It is not everyday that someone's name becomes inextricably linked with God. But it is not everyday that someone comes up with a theory that could help to unify the many disparate forces of the universe.

All the more strange, then, for the man behind the sub-atomic "God particle" to be an unassuming grandfather living in modest retirement in one of the more sedate districts of Edinburgh.

Professor Peter Higgs, 78, is a theoretical particle physicist, and it took him 20 years before he could even bring himself to call the God particle by its more scientific name - the Higgs boson. Up to that point, he preferred the more prosaic term, "scalar boson".

He still squirms when people refer to it by the deified moniker coined many years ago by a colleague. He first formulated the theory behind the sub-atomic particle named after him in the 1960s, and for almost half a century it has remained as elusive as stardust. That could all change later this year, however, when one of the world's biggest experiments is switched on deep beneath the Alpine meadows on the Franco-Swiss border, the home of the European Centre for Nuclear Research (Cern) near Geneva.

Within a 27km-long, underground ring, atom will be smashed into atom at something approaching the speed of light.

The machine, called the Large Hadron Collider (LHC), is designed to produce energy levels expected to be powerful enough to shake out the elusive Higgs boson from its seemingly inescapable prison within the atomic nucleus.

The Higgs is just one of the discoveries that the LHC is expected to make. The team of physicists behind the project believes the LHC will produce a jewel box of discoveries that will light up the infinitesimally small world of sub-atomic physics.

"The actual discovery of the Higgs boson, if it happens, is only one part of the programme. There is vastly more for the machine to do," Professor Higgs said.

"I'm most excited, for instance, about the possible identification of super-symmetry particles - symmetrical particles of the particles we already know."

Super-symmetry refers to the "grand dance" of particles in the universe. We know about a dozen sub-atomic particles, with exotic names such as quark, lepton and neutrino. Yet for every kind of particle, there may a super-symmetrical partner.

The trouble is, we can only see one of the partners in each dancing couple, with the "significant others" remaining invisible.

If super-symmetry is confirmed by the LHC it will help scientists towards the ultimate goal of a unified theory for the fundamental forces of nature - in particular the force of gravity which so far lies outside the realm of the forces known at the quantum level of the sub-atomic particle.