### The Milky Seas
Indian Ocean — Trillions of glowing bacteria light up a patch of ocean the size of Connecticut, and nobody knows how.
When sailors reported sailing through a glowing, milky-white ocean that looked like a flat field of snow, people thought they were crazy. But satellites passing over the Indian Ocean proved them right. Unlike standard ocean bioluminescence caused by algae called dinoflagellates—which flash only when disturbed by a boat or a wave—the Milky Seas emit a steady, continuous glow. The culprits are luminous bacteria called Vibrio harveyi.
These bacteria use a chemical communication system called "quorum sensing." Once they gather in mind-boggling numbers—an estimated 100 million cells per milliliter of water—they collectively trigger their glow. Biologists hypothesize they "scream" with light to attract fish, hoping to get swallowed so they can live comfortably inside a nutrient-rich fish gut. When they gather, they can light up 100,000 square kilometers of ocean, a patch roughly the size of Connecticut.
But here is the mystery: How do they pull this off? To reach such impossible density in the open ocean, the bacteria must be colonizing a massive food source, like a colossal algal bloom or a blizzard of decaying "marine snow." Even weirder, scientists have no idea how these giant glowing patches manage to stay completely stable for weeks at a time without being ripped apart and dispersed by wild sea currents.