Xenon

Xenon is a heavy, colorless noble gas found at only about 0.09 parts per million in air, from which it is extracted as a byproduct of making oxygen. William Ramsay and Morris Travers discovered it in 1898; its name comes from the Greek for stranger. In 1962 Neil Bartlett used xenon to make the first compound of a noble gas, overturning the idea that these gases never react.

Xenon gives an intense, daylight-like light in car headlights, cinema projectors and camera flashes. It is the favored fuel for the ion thrusters that steer many satellites and space probes. It also works as an anesthetic and is used in some chipmaking steps.