What about the riddle of dark matter? Scrutiny of the motion of distant galaxies indicates that they are subject to more gravity than their visible matter could possibly account for. There must be some exotic hidden matter in the mix. A theory called supersymmetry could account for this: It states that every fundamental particle had a much more massive counterpart in the early universe. The electron might have had a hefty partner that physicists refer to as the selectron. The muon might have had the smuon. The quark might have had ... the squark. Many of those supersymmetric partners would have been unstable, but one kind may have been just stable enough to survive since the dawn of time. And those particles might, at this very second, be streaming through your body without interacting with your meat and bones. They might be dark matter.

By smashing pieces of matter together, creating energies and temperatures not seen since the universe's earliest moments, the LHC could reveal the particles and forces that wrote the rules for everything that followed. It could help answer one of the most basic questions for any sentient being in our universe: What is this place?

There's one puzzle piece in particular that physicists hope to pick out of the debris from the LHC's high-energy collisions. Some call it the God particle.

The first thing you learn when you ask scientists about the God particle is that it's bad form to call it that. The particle was named a few years back by Nobel Prize-winning physicist Leon Lederman, who has a knack for turning a phrase. Naturally the moniker took root among journalists, who know a good name for a particle when they hear one (it beats the heck out of the muon or the Z-boson).

The preferred name for the God particle among physicists is the Higgs boson, or the Higgs particle, or simply the Higgs, in honor of the University of Edinburgh physicist Peter Higgs, who proposed its existence more than 40 years ago. Most physicists believe that there must be a Higgs field that pervades all space; the Higgs particle would be the carrier of the field and would interact with other particles, sort of the way a Jedi knight in Star Wars is the carrier of the "force." The Higgs is a crucial part of the standard model of particle physics—but no one's ever found it.

Theoretical physicist John Ellis is one of the CERN scientists searching for the Higgs. He works amid totemic stacks of scientific papers that seem to defy the normal laws of gravity. He has long, gray hair and a long, white beard and, with all due respect, looks as if he belongs on a mountaintop in Tibet. Ellis explains that the Higgs field, in theory, is what gives fundamental particles mass. He offers an analogy: Different fundamental particles, he says, are like a crowd of people running through mud. Some particles, like quarks, have big boots that get covered with lots of mud; others, like electrons, have little shoes that barely gather any mud at all. Photons don't wear shoes—they just glide over the top of the mud without picking any up. And the Higgs field is the mud.