Paul Blow
TO GET to the very bottom of physics, there has always been one rule: size matters. The first particle smashers of the early 1960s were little wider than a dining room table. A decade later, the Tevatron, a circular collider in the US, had a circumference of 6 kilometres. Today’s largest machine, the Large Hadron Collider (LHC), has one four times as long. Now there are plans to build colliders 100 kilometres in circumference: about the size of New York City.
Physicists get a lot of flak for these enormous – and enormously expensive – aspirations. Nature is tenacious, however, and wresting its most closely held subatomic secrets from it has always meant accelerating particles over longer and longer distances before smashing them together. But a new shortcut is emerging in a weird, cloud-like state of matter known as a plasma. Inject particles into this febrile stuff, and they can accelerate a thousand times faster than before.
This is more than wishful thinking. Plasma accelerators have been advancing steadily over the past few decades, and while they have yet to pose a serious threat to the dominance of conventional facilities, that might be changing. Several recent developments suggest that plasma accelerators could soon give big beasts like the LHC a run for their money. Ultimately, the hope is that these small machines will let us tackle some of the biggest questions in physics: why our universe is filled with matter and not antimatter, for instance, or what constitutes dark matter. It seems the ironclad rule of particle physics is about to be broken.
Certainly, technology everywhere else is shrinking. But conventional …
