When light knocks an electron out of an atom, it flies off like a ball thrown into a crowd. Scientists have long wanted to know the exact moment each electron leaves the atom, but direct measurement disturbed the very process. Now physicists have proposed a method that uses a second light pulse to 'photograph' the moment of the electron's birth.
The method is like the interplay of two waves on water: one wave from the first electron, another from a second electron created by a short pulse. When the waves meet, they add up, and from the resulting pattern you can calculate when the first electron appeared. It's like reading the ripples on a pond to know when a stone was dropped.
This approach not only measures time but also reveals how the electron's energy relates to its moment of birth. It opens the door to understanding the fastest processes in nature — from chemical reactions to the workings of future electronics.
An attosecond is one billionth of a billionth of a second. In one attosecond, light travels a distance smaller than the diameter of an atom.
In the series 'Star Trek', sensors instantly analyze subatomic processes, the new method brings science closer to such precision.