A milky sea sprawling across almost 40,000 square miles of ocean south of Java in summer 2019 was captured by sensitive night-vision satellites; it lasted 45 days. Learn how scientists use night-light sensing satellites to detect rare events of milky seas, a form of marine bioluminescence that looks like a snow field on the ocean. See images of milky seas across the Indian Ocean and Western Pacific, and how they are linked to algae and bacteria. Milky seas are a luminous phenomenon in the ocean caused by luminous bacteria. They appear as large areas of seawater that glow diffusely and continuously in varying shades of blue, and can be seen from satellites. What Is The Milky Sea Phenomenon? The Milky Sea Phenomenon is a rare, natural phenomenon where large areas of the ocean glow vibrantly. This glow sometimes covers over 100,000 square kilometers, appearing as a soft, bluish-white milky light. Unlike the glowing waves often seen near beaches (known as bioluminescence), Milky Seas glow continuously and uniformly, like a blanket spread across the ocean.
