Randomness, the lack of a definite pattern or predictability, is usually undesirable in scientific inquiries. Often it poses a nuisance to be overcome by repeated measurements and statistical analysis; in some cases (e.g., at atomic and subatomic scales governed by quantum mechanics), it is an essential property of the system, setting an insurmountable limit to the predictive power of our theory. Nevertheless, randomness in the genetic machinery of neurons has been ingeniously exploited with stunning effects.

Two kinds of events evade the naked eye: those happening too slowly to be noticeable, and those happening too fast to be discerned. While a natural process usually cannot be accelerated for observation, technology has enabled people to catch the moment when a fast process occurs and record it as impressive images.