A Nobel prize for electron-watchers

INSIDE ATOMS, things move fast. An electron zooms around a nucleus, changing its position or energy in mere fractions of an attosecond. An attosecond is a billionth of a billionth of a second—a unit of time so short that there are as many attoseconds in a single second as there have been seconds since the Big Bang, 13.8bn years ago.Watching electrons flying around is, therefore, tricky. This year’s winners of the Nobel prize in physics, however, worked out a way to do it. Pierre Agostini, Ferenc Krausz and Anne L’Huillier showed that it is possible to build lasers that could flash on and off so quickly that each pulse of light lasted for only a few hundred attoseconds. These pulses of light could then be used to take snapshots of the movements of electrons.