Marine scientists have discovered a previously unknown jellyfish species glowing with bioluminescence in total darkness nearly 4,000 meters below the ocean surface. At these extreme depths, sunlight never penetrates, yet the jellyfish produces its own light—likely for communication, camouflage, or defense—highlighting how much of Earth’s deep ocean remains unexplored. Key Facts: • Discovered at ~4,000 m depth • Lives in complete darkness • Produces natural bioluminescent light • Found during dee