Irony alert: radio astronomy organization hands out fitness devices that threaten interference to radio-telescope operation. Wrist-worn activity monitors like the Fitbit are good for radio astronomers. But not so good for radio astronomy. Much as traditional astronomers use optical telescopes to see with visible light, radio astronomers use “radio telescopes” to observe distant objects by the radio waves they emit. With huge antenna dishes that focus on selected points in the sky, these telescopes are the most sensitive radio receivers on the planet. That makes them highly vulnerable to interference from other radio sources. The biggest steerable radio telescope in the world, and probably the most sensitive, is at the National Radio Astronomy Observatory (NRAO) in Green Bank, West Virginia. Having a dish 100 meters across and an antenna boom that makes it 60 percent taller than the Statue of Liberty, this is the world’s largest moving object on land. To…
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