Xenon is a noble or inert gas used mainly for its light-emitting properties in products like photographic flash lamps, automobile headlights and fog lights, bactericidal lamps, strobe lamps, electron tubes, and lamps used to excite ruby lasers. Because xenon is one of the heaviest gases available, it is also often utilized in situations where a gas with high molecular weight is necessary.
Xenon is also used for high-intensity arc lamps for motion picture projection and ultraviolet light and in nuclear energy bubble chambers. Light products that utilize xenon as a functionary compound produce much higher levels of light than conventional bulbs at a lower cost of power. While it is normally colorless, xenon produces a bright blue light when it is electrically excited, which is evident in the blue appearance of xenon automobile headlights. These headlights use less energy than conventional headlights, but they require high voltage to excite the xenon. Xenon is a rare element found in the atmosphere, and as of 2014, the only way to obtain xenon is through commercial processes to extract it from the air. This can only be done at industrial liquid-air plants because xenon is chemically non-reactive, which also makes it odorless and tasteless.