When you hear the word bioluminescence, do you think of glowing ocean waves under a dark sky? Many do. But, bioluminescence includes all life that – through a chemical reaction – emits light. In the image above, a single-celled form of marine plankton, known as bioluminescent dinoflagellates, are the source of the light on the incoming waves. But in addition, there are bioluminescent creatures in the deeper ocean, too. And we here on Earth’s dry land sometimes see bioluminescent creatures flying in the air.