In 1958, the United States Government declared a 180 km by 190 km area as the National Radio Quiet Zone. On the border between Virginia, West Virginia and Maryland, the area surrounds the National Radio Astronomy Observatory in Greenbank, West Virginia. At its centre is the Robert C. Byrd Green Bank Telescope, the largest land-based moveable object on the planet.

The telescope is said to be sensitive to ‘a billionth of a billionth of a millionth of a Watt… the energy of a snowflake hitting the ground’. The Quiet Zone restrictions ban mobile phones, baby monitors, microwave ovens and wireless doorbells. Even petrol driven cars are not allowed within a mile of the telescope due to the electromagnetic emissions from their spark plugs. Enforcement officers patrol the local area looking for sources of radio frequency emissions.