"Milky seas" sound like something ripped out from the pages of maritime lore but they are a genuine, yet rarely seen, occurrence.
Real-world photos of this stunning natural phenomenon taken by a group of sailors in 2019 have now been published for the first time.
The infrequency and remoteness of milky seas, when the night-time ocean mysteriously glows white, have stumped scientists over the years.
But one theory is that it is caused by bioluminescent bacteria communicating with each other.
Steven Miller, a professor of atmospheric science at Colorado State University, believes that only " handful of people currently alive " have seen the unique event.
Last year, Miller and his team published satellite images in Scientific Reports of a what they thought could potentially be milky seas, including one from August 2019 off the coast of south Java, Indonesia.
This coverage prompted Naomi McKinnon to contact Miller claiming that she had possibly witnessed the same event near Java while sailing around the world.
McKinnon was part of a seven-person crew on board a yacht called Ganesha when they saw one night that the "sea was white" - despite there being no Moon - and liked it to "sailing on snow".
The strange lighting lasted through until dawn and the yacht's captain said the glow seemed to emanate from around 10-metres below the surface, which rejects some scientists beliefs that milky seas are a thin film sitting on top of water.
The crew took photos of it on their phones and digital cameras, which were then shared with Miller and published in Proceedings of the National Academy of Sciences to provide the first photographic evidence of milky seas.
Miller said: “To this point it’s all been word of mouth, dating back to the earliest times of the trade ships in the 18th century.
"They’ve all kind of described a similar thing, and the pictures are consistent with what they’ve described – it’s a kind of uniform, ethereal glow, almost a foggy appearance, very disorienting.”
He hopes that studying the rare marine phenomenon should now be easier following the Ganesha crew's testimony and will allow properly-equipped research ships sample and reveal what turns the water white.
