Many great minds — Democritus, Isaac Newton, James Clerk Maxwell, Albert Einstein — took giant steps toward bringing the universe's lost unity out of hiding. In 1964, Peter Higgs, a shy scientist in Edinburgh, added his name to that list by coming up with an ingenious theory that gave scientists the tools to explain how two classes of particles, which now appear to be different, were once one and the same. His theory proposes the existence of a single particle responsible for imparting mass to all things — a speck so precious it has come to be known as the "God particle.

proposes the existence of a single particle responsible for imparting mass to all things — a speck so precious it has come to be known as the "God particle." The scientific term for it is the Higgs boson, and to find it physicists are counting on the most powerful particle accelerator ever constructed: the Large Hadron Collider (LHC) at the CERN laboratory in Geneva, a 17-mile underground circuit that took 25 years to plan and $6 billion to build.

What the critics are in such a lather about is the $8-billion Large Hadron Collider, a massive assemblage of iron, steel and superconducting wire 300 feet underground in a 17-mile-long circular tunnel on the Franco-Swiss border.

The most complex piece of scientific equipment ever built, the collider will send particles crashing into each other at just a wink shy of the speed of light, generating energies more powerful than the sun.

GENEVA -- Michelangelo L. Mangano, a respected particle physicist who helped discover the top quark in 1995, now spends most days trying to convince people that his new machine won't destroy the world.

"If it were just crackpots, we could wave them away," the physicist said in an interview at the European Organization for Nuclear Research, known by its French acronym, CERN. "But some are real physicists."