Sprites (also known as Transient Luminous Events, or TLEs for short) are large scale electrical discharges that occur high above thunderstorms in the upper atmosphere. They are massive phenomena, sometimes 50 km high and 50 km wide. They are commonly incorrectly referred to as "upper-atmospheric lighting" but they are much, much cooler than the blazing temperatures of ground lightning. The reason sprites glow red is because of the nitrogen molecules in the atmosphere that when excited by electrical discharges glow a red-orange color in the lower ionosphere and turn to a blue-purple glow just above the cloud decks.