Hackers have broken into the network of the Swiss particle-physics laboratory operating the Large Hadron Collider that began smashing atoms this week.

The hackers, calling themselves the "Greek Security Team," defaced the CERN Web site with comments made in Greek, according to the Daily Telegraph, which reported the incident today. CERN has now taken down this public-facing Web site, and according to the Telegraph, CERN spokesman James Gillies said, "There seems to be no harm done."

It's not believed that the Greek Security Team hackers -- thought to be targeting the Compact Muon Solenoid Experiment (CMS) that is using the Large Hadron Collider to make new discoveries about particle physics -- were able to penetrate further into the CERN network of control systems for the giant collider.

The collider is undertaking a ground-breaking experiment to find key particles of matter that scientists hope will help explain the evolution of the universe. The Telegraph quotes CERN spokesman Gilles as acknowledging the hackers made the point that CMS is hackable.

The Greek Security Team is not a generally known hacker group, according to Graham Cluley, senior technology consultant at Sophos who is in the U.K. and following developments regarding the security breach at the CERN facility.

The message the hackers left on the defaced Web page in Greek hasn't been translated yet, but Cluley said his initial impression is that this hacker activity against the famous particle-physics experiment was done mainly to gain publicity for the hackers, not disrupt the scientist's work.

"I'd be surprised if they're trying to disrupt this," said Cluley.