Attosecond X-ray Flashes from an Accelerator
An ordinary camera flash lingers for hundredths of a second, but for atoms, that's an eternity. Inside molecules, electrons jump in attoseconds: billionths of a billionth of a second. To capture that, you need a light pulse shorter than the event itself.
Physicists take an electron beam in a linear accelerator and compress it so that individual bunches become thinner than a hair — in time.