Flashes

Flashes are brief bursts of light produced by natural phenomena or human-made devices. They are defined by short duration and high brightness, delivering a pulse of photons in a very short time.

Natural flashes occur in multiple contexts. Lightning creates atmospheric discharges with bright, momentary flashes often accompanied by thunder. Meteors can produce quick flashes as they burn up in the atmosphere. Some animals, such as fireflies, emit recurring light pulses, while auroras can present brief intensifications of light in the sky.

In photography and film, a flash unit emits a brief, intense burst to illuminate a scene. Modern cameras and external strobes use xenon or LED light sources and synchronize with shutters to control exposure. Flash lighting enables daytime-supplementation, fill flash for shadows, or artistic effects. Portable flash units vary in power, duration, and recycle time, influencing how quickly they can fire again.

Arc flash describes a hazardous electrical discharge that can generate a bright, high-energy flash. Safety protocols address arc flash energy, establish safe working clearances, and require protective equipment during electrical maintenance.

Flash memory is a type of non-volatile storage. Data remains stored without power and it is widely used in solid-state drives, USB drives, memory cards, and embedded devices.

Flashes are described by duration, peak brightness, and color temperature, with durations ranging from microseconds in electronic devices to milliseconds in natural phenomena.