Since the 17th century, "milky seas" have been associated more commonly with maritime folklore than scientific knowledge. They are mentioned in the Jules Verne classic 20,000 Leagues Under the Sea. Until this satellite detection was achieved by NRL researchers, the phenomena had only been reported in ship's logs and their descriptions were subject to the uncertainties of human perception. Mariners have described the phenomena as giving the impression of sailing upon a field of snow or gliding over the clouds--all under the darkness of a moonless night. The glowing waters appear to extend to the horizon in all directions, and can last from several hours to several days. They are thought to be caused by enormous populations of bacterial bioluminescence, but their ephemeral nature has made it difficult to place appropriately equipped research craft in their locations.
Dr. Steven Miller, from NRL's Marine Meteorology Division, explained that the milky sea presented in the paper was detected by the Defense Meteorological Satellite Program (DMSP). These polar-orbiting satellites feature the Operational Linescan System (OLS) instrument, which was designed primarily to monitor global cloudiness under both solar and lunar illumination. To achieve nighttime detection, the OLS uses a sensor capable of registering extremely low levels of visible light. This system has been used to detect terrestrial and atmospheric emission sources such as fires, lightning, and human activit
Source:Naval Research Laboratory