The builders of the world's biggest particle collider are being sued in federal court over fears that the experiment might create globe-gobbling black holes or never-before-seen strains of matter that would destroy the planet. Representatives at Fermilab in Illinois and at Europe's CERN laboratory, two of the defendants in the case, say there's no chance that the Large Hadron Collider would cause such cosmic catastrophes. Nevertheless, they're bracing to defend themselves in the courtroom as well as the court of public opinion.

The Large Hadron Collider, or LHC, is due for startup later this year at CERN's headquarters on the French-Swiss border. It's expected to tackle some of the deepest questions in science: Is the foundation of modern physics right or wrong? What existed during the very first moment of the universe's existence? Why do some particles have mass while others don't? What is the nature of dark matter? Are there extra dimensions of space out there that we haven't yet detected?

Some folks outside the scientific mainstream have asked darker questions as well: Could the collider create mini-black holes that last long enough and get big enough to turn into a matter-sucking maelstrom? Could exotic particles known as magnetic monopoles throw atomic nuclei out of whack? Could quarks recombine into "strangelets" that would turn the whole Earth into one big lump of exotic matter?

Former nuclear safety officer Walter Wagner has been raising such questions for years - first about an earlier-generation "big bang machine" known as the Relativistic Heavy-Ion Collider, and more recently about the LHC.

Last Friday, Wagner and another critic of the LHC's safety measures, Luis Sancho, filed a lawsuit in Hawaii's U.S. District Court. The suit calls on the U.S. Department of Energy, Fermilab, the National Science Foundation and CERN to ease up on their LHC preparations for several months while the collider's safety was reassessed.

"We're going to need a minimum of four months to review whatever they're putting out," Wagner told me on Monday. The suit seeks a temporary restraining order that would put the LHC on hold, pending the release and review of an updated CERN safety assessment. It also calls on the U.S. government to do a full environmental review addressing the LHC project, including the debate over the doomsday scenario.

On Monday, District Judge Helen Gillmor assigned the case to a magistrate judge, Kevin S.C. Chang, for an initial conference on June 16. Wagner said he planned to ask for a more immediate hearing on the request for a restraining order - that is, once he has served the federal government with the court papers.

The case is currently being handled by the U.S. attorney's office in Hawaii, where Wagner and Sancho both live,`but that may not necessarily be where the legal proceedings end up. The Justice Department's Environmental and Natural Resources Division, based in Washington, is also being brought in on the case, assistant U.S. attorney Derrick Watson told me in an e-mail Wednesday.

In Washington, Justice Department spokesman Andrew Ames noted that the court papers had not yet been received. "We don't have any comment," he told me Thursday. "We'll comment in court when it's appropriate."