Auroras occur when particles from space bombard gases in the atmosphere, causing the release of specks of light. The color of an aurora is determined by the type of gas that is hit and where is it located in the Earth’s atmosphere. Oxygen can produce green and red light depending on the altitude it is excited at, while nitrogen can produce blue or pink light, depending on altitude. Sometimes the emitted light can appear to mix, creating the appearance of purple, pink, or even white auroras.