Corrects paragraph 5 to ... a total power of 7 billion billion electron volts instead of 7 billion

GENEVA - Physicists at the CERN research center delayed attempts on Tuesday to create mini-versions of the Big Bang after what they called minor technical problems blocked the launch of the marathon experiment.

The experiment at the European Center for Nuclear Research (CERN) aims to recreate the conditions of the Big Bang that led to the birth of the universe 13.7 billion years ago to examine the nature of matter and the origin of stars and planets.

After a trouble-free overnight test run, first a small power supply glitch and then an over-sensitive magnet safety system led the physicists to suspend at least for a few hours the mega-power particle collisions, the focus of the world's largest scientific experiment.

It's disappointing, but we are confident that we shall still get collisions today, said Oliver Buchmueller, one of the key figures on the 10 billion Swiss franc ($9.4 billion) project. Still it does look like a long day ahead.

The collisions are due to take place at a total power of 7 billion billion electron volts (eV) and at a nano-fraction of a second slower than the speed of light in CERN's 27 km (16.8 mile) Large Hadron Collider (LHC), hundreds of metres (feet) below the Swiss-French border.

After the problems arose as beams were injected into the collider in the early morning, CERN officials were quick to dismiss any suggestion that it was a repeat of a major incident in September 2008 that seriously damaged parts of the experiment and delayed the full launch of the project until now.

These are really minor issues, said CERN spokeswoman Renilde Vanden Broeck. They can be quickly solved.

CERN engineers said they expected to start trying again for collisions around 1030 GMT.

During the coming months and years, CERN scientists expect the project to lift the veil on some of the mysteries of the cosmos -- how matter was converted to mass after the fireball of the Big Bang and what is the dark, or invisible, matter that makes up an estimated 25 percent of the universe.

(Editing by Jonathan Lynn/David Stamp)