Asked by Harry Blythe

Glowworms, a disparate nomenclature for a disparate collection of insects (none are actual worms) glow via a variety of different methods, but all emit light via bioluminescence. Bioluminescence is a naturally occurring form of chemiluminescence where energy is released by a chemical reaction in the form of light. For example, in phengodes glow is produced and emitted from giant solitary cells within the abdomen, while in arachnocampa it is emitted through modified excretory organs.

In addition, glowworm bioluminescent organs vary widely in size, location and structure, indicating that the different species’ glowing abilities evolved independently of one another. This is supported by the reasons for producing the glow, which range from attracting a mate through to warding off predators and luring prey into sticky webs for consumption, the latter characteristic of the platyura species.

From air-sea rescue to counter surveillance, night vision goggles have literally changed the way we see

Night vision typically utilises two types of technology; thermal imaging (infrared) and image intensification or light enhancement, of which the latter is the most portable and therefore suitable for use in night vision goggles. Light Enhancement devices take the photons present in ambient light (typically moon or starlight) from the front lens, pushing them through a photocathode tube that converts them into electrons, a microchannel plate containing millions of photoelectric channels that multiplies them before bouncing them against a phosphor screen to convert back into the distinctive green-tinged image seen through the eyepiece.

Night vision was first developed for tanks by both sides in WWII before being made portable for sniper scopes in Vietnam and finally for goggles in the Fifties. Now used by military, police and rescue operations worldwide, devices are classified as Generations 0-3, with consumer (Gen 1) devices starting from as little as £200 to far more expensive and sophisticated Gen 3 devices for military and counter-surveillance purposes.