A Mysterious Red Glow

Abstract

Among living things, many ocean organisms, ranging from bacteria to fish, exhibit bioluminescence. The most familiar example of bioluminescence to us is fireflies. Written record of this phenomenon goes back to 1000 bc. in the Chinese Book of Odes (Shi Jing). The Roman Army commander and philosopher Pliny the Elder (23–79 ad) recorded in his book Naturalis Historia descriptions of fireflies, glowworm, jellyfish, luminous mushrooms, and glowing wood. In Chinese folklore, there is a story about a diligent student in the Jin dynasty (265–420 ad) studying at night using the light of captured fireflies in a bag for illumination. Before the widespread use of artificial lighting in the twentieth century, natural light sources arouse great interest from ancient people. One can easily imagine the wonder and fear from the observations of a glowing rotten log, which was interpreted as coming from an evil spirit but we now know to have originated from luminous fungi. These natural light sources are different from other forms of light which is associated with heat, as in cases of burning wood or candle flames. Aristotle referred these luminescence phenomena as “cold light”.KeywordsSilver ChloridePlanetary NebulaInterstellar SpaceInfrared SourceAstrophysical JournalThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.