گرین بانک در ایالت ویرجینیای غربی آمریکا، جائیست که هیچ کدام از تجهیزات مخابراتی از جمله شبکه تلفن، تلفن همراه، اینترنت و حتی گیرنده ها و فرستنده های رادیویی و تلویزیونی نمی تواند در آنجا احداث شود که این موضوع دلیل خاصی دارد.
Green Bank, in Pocahontas County in West Virginia, the United States, is possibly one of the quietest residential places on earth. There is no cell phone reception here, no Wi-Fi, not even radio and television. But Green Bank is not technologically backward. On the contrary, it’s home to the world''s largest fully steerable radio telescope on earth – the Robert C. Byrd Green Bank Telescope (GBT), operated by the National Radio Astronomy Observatory. The GBT is the reason why this town is electromagnetically silent.
Radio telescopes work by detecting electromagnetic waves that come from distant galaxies. These signals are so faint that the slightest emission of radio waves from electronic gadgets can interfere with the readings of the radio telescopes. For this reason, all cell phones, Wi-Fi, radio and other communication devices are outlawed here. There are no cell phone towers for miles around, no music plays on the radio or soap operas on the television. Not even petrol cars are allowed because gasoline engines use spark plugs to ignite the fuel-air mixture, and electric sparks produce electromagnetic waves.