No one keeps track of time better than Ferenc Krausz. In his lab at the Max Planck Institute of Quantum Optics in Garching, Germany, he has clocked the shortest time intervals ever observed. Krausz uses ultraviolet laser pulses to track the absurdly brief quantum leaps of electrons within atoms. The events he probes last for about 100 attoseconds, or 100 quintillionths of a second. For a little perspective, 100 attoseconds is to one second as a second is to 300 million years.