The world's most expensive and powerful physics experiment goes live tomorrow when protons will be circulated around the Large Hadron Collider (LHC) for the first time.

The Cern experiment hopes to discover exotic forms of matter, particularly the Higgs boson, or 'God', particle.

Scientists believe that Higgs boson may be able to explain the origin of mass, something the current standard model of the universe cannot explain.

The cost of the experiment has been put at anything between €3bn and €6bn. The UK's contribution has been reckoned by academics as £34m a year, or less than the price of a pint of beer per adult in the UK per year.

Protons have already been allowed into the experiment as a check on the actual injection process, but tomorrow they will circle the 27km around the system and be allowed to cross the France-Switzerland border without customs formalities.

Initially the proton beam energy will be relatively low compared with the final projected energy of around seven tera-electron-volts (TeV), giving a top speed of "eight nines", or 99.9999991 per cent of the speed of light.

Even seven TeV pales compared with the collision energy that LHC will let loose when it uses lead ions - 1150 TeV or 1.15 peta-electron-volts.

Tomorrow's proton injection process has drawn huge attention, especially after scare stories that the experiment could destroy the Earth.

The LHC Safety Assessment Group has produced a study (PDF) intended to reassure people, after increasingly alarming reports suggested that the experiment might lead to the creation of microscopic black holes which would then devour the planet.

"Specifically, we study the possible production at the LHC of hypothetical objects such as vacuum bubbles, magnetic monopoles, microscopic black holes and strangelets, and find no associated risks," said the authors of the report.