The shape of things to come

摘要

Countless times each day inside the world's atom smashers, subatomic particles collide head-on and then break up in elaborate dances. A zillionth of a second later they reach more stable states, and then fly away, eventually reaching detectors. It doesn't only happen in experiments. This is also the story of the universe. Particles created in the big bang flew apart, eventually combining into larger particles, atoms, planets, trees and people as the universe expanded. It's like what goes on inside an atom-smashing particle accelerator, only the universe is a huge, slow-motion experiment, playing out over billions of years. Or is it? For years, physicists have used this analogy between atom smashers and the universe as a guiding principle towards the elusive theory of everything. The main reason for this is that the atom smasher idea happens to fit well with string theory - the theory that replaces subatomic particles with tiny vibrating "strings", and is supposed to describe the whole universe and unify all of physics.