Defense Meteorological Satellite Program
"At first sight, the ocean seemed lactified," wrote Jules Verne in his 1869 science fiction novel "Twenty Thousand Leagues Under the Sea."
Lactified? Yep, that was Verne's cute way of saying the ocean looked milky. And he wasn't the first person to describe a "sea of milk" in the Indian Ocean. Since the 17th century, sailors have reported sightings of strange, milky-white waters, stretching as far as the eye can see. For the most part, these reports were shrugged off as tall tales. But it turns out the milky seas are real.
In 2005, scientists revealed that they'd reviewed data collected via satellite sensors to confirm a "milky sea" sighting made by British sailors in January 1995, according to ScienceDaily. The satellite data showed a large area of low-level light about the size of the state of Connecticut in the northwestern Indian Ocean, which is where the sailors were at the time of the sighting. To give you an idea what those sailors saw, here's the written account transmitted from the British vessel in 1995 (via scientist Steven D. Miller):
"On a clear moonless night while 150 miles east of the Somalian coast, a whitish glow was observed on the horizon and, after 15 minutes of steaming, the ship was completely surrounded by a sea of milky-white color with a fairly uniform luminescence. The bioluminescence appeared to cover the entire sea area, from horizon to horizon ... and it appeared as though the ship was sailing over a field of snow or gliding over the clouds."
Doesn't it sound wonderful?
Bioluminescent bacteria are responsible for the creamy white seas. While scientists aren't sure why these bacteria congregate at certain times, they do know they're capable of emitting a faint glow over a period of days, according to Miller. One bacteria doesn't emit that much light. But when 40 billion trillion of these little guys concentrate in one area, there's quite a shine, according to ScienceDaily. The sea becomes lactified!