| Hint | Light Source |
| Rapid oxidation of a material, releasing light, heat and other biproducts | |
| An atmospheric lightshow that appears when charged particles from the Sun interact with ionospheric ions | |
| Even when other light sources are removed, this weak emission of light remains in the night sky | |
| Quick discharge of electricity due to electrical charge build-up within clouds | |
| Light by bioluminescence | |
| Liquid rock | |
| From beyond earth's atmosphere | |
| Caused by particles ionizing within this gas | |
| Caused by breaking of chemical bonds when materials are pulled apart or damaged | |