So far, so good for 'Big Bang machine'

Scientists today launched the "Big Bang experiment" - an attempt to recreate the start of the universe using the biggest and most complex machine yet built.

The €6.2bn Large Hadron Collider was powered up without a hitch at CERN, the European nuclear research organisation in Geneva.

After a tense first hour researchers announced they had achieved "full beam", meaning that a stream of sub-atomic particles was racing round the LHC's 27 kilometre-long circular tunnel at just less than the speed of light. The next stage will be to fire a beam in the opposite direction.

The eyes of the world were on LHC project leader Dr Lyndon Evans, from Aberdare in south Wales, in the run-up to the "switch-on".

Looking relaxed in a short-sleeved shirt and jeans, Dr Evans counted down the last few seconds before the first beam of protons was put into the LHC.

"Five, four, three, two, one, zero - nothing," he joked before a blip appeared on a computer monitor signalling that the long years of hard work had paid off and the machine was working.

Dr Evans, whose father was a coalminer, said: "This is really the biggest and most complex scientific project ever undertaken, and you cannot do a thing like this without engineers and applied scientists of very top quality."

The LHC, which took two decades to construct, is the largest particle accelerator the world has seen.

It is designed to smash protons - one of the building blocks of matter - into each other with energies up to seven times greater than any achieved before.

In the flashes from the collisions, scientists expect to reproduce conditions that existed during the first billionth of a second after the Big Bang at the birth of the universe.

No one knows precisely what will come tumbling out of the primordial soup of disintegrating protons.

But the scientists have dismissed suggestions that the experiment could somehow cause the end of the world.

The LHC could help scientists explain mass, gravity, mysterious "dark matter" and why the universe looks the way it does.

It could also produce the first evidence of extra spatial dimensions and even create mini-black holes that blink in and out of existence in a fraction of a second.

The LHC, housed in the 27km (17 mile) tunnel under 100m of rock, straddles the borders of Switzerland and France between Lake Geneva and the Jura mountains.

"Turning on" the machine was a lot more complex than flicking a switch.

Atoms of hydrogen housed in a bottle no bigger than a fire extinguisher were first stripped of their electrons to reveal naked protons.

These particles then had to be fired through a succession of smaller accelerators before they were travelling at sufficient speed to be injected into the LHC.

It was a process that required unimaginable levels of precision with timing accurate to within a fraction of a nanosecond.

The particles travel through a ring-shaped tunnel supercooled to just 1.9 degrees above absolute zero (minus 271C), the lowest temperature allowed by nature.

Reaching velocities of 99.99% of the speed of light, each beam will pack as much energy as a Eurostar train travelling at 150km per hour.

The protons will be brought together in four huge "detectors" placed along the ring. Each detector is like a giant microscope, designed to probe deeper into the heart of matter than has been possible before.

Concerns have been voiced, in particular by German chemist Professor Otto Rossler, that black holes created by the LHC will grow uncontrollably and "eat the planet from the inside".

But those involved in the project insist they have reviewed all the evidence and concluded that it poses no risk to the universe.

The first particle collisions are likely to take place within a few weeks.

In some cases, teams of more than 2,000 collaborating scientists will be sifting and analysing data from the machine.

Most will not be at the LHC's operating base at CERN.