Set Sail for the Milky Seas!

Above: Satellite imagery of the "Milky Seas" off the coast of Java in 2019. CSU/CIRA and NOAA/NESDIS

For the very first time, a mysterious oceanic phenomenon has been photographed and documented firsthand. For centuries, sailors across the world have reported seeing long stretches of glowing water, inspiring maritime legends and folklore. For sailors far from home, the effect must have been incredibly amazing and perhaps even frighteningly bizarre. Today though, we know quite a bit more about how the waves get their glow.

Dubbed “milky seas,” the phenomenon is caused by bioluminescent bacteria emanating a radiant blue light, sometimes for tens of thousands of square miles. These patches of oceanic light had been previously observed with the aid of satellite technology, but now we have a firsthand picture of these milky seas.

The photos were taken aboard a sailboat off the coast of Java in 2019; as the sun set, the crew found themselves in the midst of a milky sea the size of Iceland. The photos from aboard the ship are of low quality, but even in the darkness you can clearly make out glowing white waves beyond the deck of the ship.

On the other side of the planet, Steven Miller, an atmospheric scientist dedicated to studying milky seas, used satellite imagery to identify this patch of ocean near Java as a potential occurrence of the phenomenon, but any further evidence. After publishing his findings though, he was contacted by a crewmember of the sailboat and received the images to support his findings.

This was the key to identifying the first images of this extremely rare ocean phenomenon. It's thought that a milky sea only occurs once or twice a year as bioluminescent plankton produce strange white light on the waves. The ocean, of course, is a pretty big place, which means you have to be in just the right place at just the right time to get a chance to witness it!