An "attosecond" is a unit of time equal to one quintillionth of a second, or 10^-18 seconds. It is used in physics to measure extremely fast processes, such as the movements of electrons within atoms. This time scale is so short that it allows scientists to observe and study phenomena that occur at the quantum level. Attosecond science has advanced significantly since the first attosecond pulses were created in the early 2000s. These pulses enable researchers to capture the rapid dynamics of atoms, molecules, and chemical reactions, providing insights into fundamental processes in quantum mechanics and paving the way for new technologies in electronics and photonics.