A new era in physics should have started 11 years ago in Waxahachie, Texas. That’s where the Superconducting Supercollider, a 54-mile-long underground circular particle accelerator, was supposed to smash protons together and glean vital clues from the subatomic wreckage. Cost overruns led Congress to cancel the SSC in 1993. If the project had gone on as planned, “by now we’d be asking a new generation of questions and refining them,” says theoretical physicist Frank Wilczek, a Nobel laureate at MIT. “But I’m on record as saying we’re about to enter a new golden age.”
The reason for his sunny mood: the Large Hadron Collider, an almost-as-powerful accelerator near Geneva that began firing protons last spring. It could provide the best evidence yet that the four natural forces shaping our world—gravity, electromagnetism, the strong force, and the weak force—are manifestations of a single underlying law. Through a decades-long effort, physicists have managed to incorporate all of the forces save gravity into a theory called the standard model. The LHC is designed to find the hypothetical particles (most notably the Higgs boson, believed to endow other particles with mass) that would back up that theory.
The LHC may also lead physicists toward a unifying framework that goes even beyond the standard model. String theory—which holds that all particles and forces ultimately consist of unimaginably small, vibrating objects called strings—has dominated theoretical physics for most of the past 30 years, yet it remains controversial. Many in the field feel the theory is valid, but it cannot be falsified by experiment, the standard by which scientific concepts are judged.
Although the LHC will not come anywhere close to detecting strings, it may confirm a precursor theory called supersymmetry, in which every known type of particle has a “superpartner”: an unstable, heavier twin. On the other hand, failure to detect supersymmetric particles at the LHC would be a blow to string theory’s credibility. “String theory has been impressive mathematically,” Wilczek says, “but disappointing in describing physical reality.”