For much of the past century, physics was an exciting, wide-ranging exploration. But to be a theoretical physicist today, you pretty much have to stake your career on one incredibly popular but pretty much unprovable notion: string theory. Since the idea that the universe is composed of small vibrating "strings" gained a following in the 1970s, the theory, which in some forms posits 10 dimensions and seeks a unifying "supersymmetry," has captured the theoretical-physics community in the U.S. The easiest way to earn an appointment is to dive head-first into a branch of string theory, which dominates the top programs at Princeton, MIT and other influential institutions. The problem is, we simply have no idea if we're on the right track, because the theory still isn't verifiable.
Lee Smolin, a physicist at the Perimeter Institute for Theoretical Physics in Waterloo, Canada, who investigates quantum gravity and string theory, believes that this physics monoculture is stifling. "Science has become too risk-averse, and its progress is being hurt as a result," he says. When CERN's Large Hadron Collider restarts later this year, however, it could end the waiting, helping to confirm parts of string theory—or dash it altogether. If supersymmetric particles called sparticles are bashed into existence: yay! But if the W boson particle does not react as hoped, that damages a central pillar of the theory. Across the U.S., whole careers are boiling down to the chance that a big box comes up with something.