By using a new technique which uses attosecond pulses, scientists can now film an electron in motion.

Previously it was impossible to photograph electrons because of their extreme speediness, so scientists had to rely on more indirect methods. These methods could only measure the effect of an electron's movement, whereas the new technique can capture the entire event.

Extremely short flashes of light are necessary to capture an electron in motion. A technology developed within the last few years can generate short pulses of intense laser light, called attosecond pulses, to get the job done.

"It takes about 150 attoseconds for an electron to circle the nucleus of an atom. An attosecond is 10^-18 seconds long, or, expressed in another way: an attosecond is related to a second as a second is related to the age of the universe," said Johan Mauritsson of Lund University in Sweden.