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The spectrum of radio waves is chopped up like the egg in an egg salad. Different chunks of spectrum are reserved for different uses: radio and TV broadcasts, cell phones, military transmissions, orbiting satellites, and many others.
Several wavelength bands are set aside for radio astronomy — the study of radio waves from the universe. The waves are produced by the remnants of exploded stars, stellar corpses, supermassive black holes, planetary magnetic fields, and many other sources. The radio waves can reveal details about these sources that astronomers can’t learn any other way.
Even with some wavelengths reserved, though, radio astronomy is facing challenges. Devices that broadcast at the surrounding wavelengths often “bleed” into the protected bands, for example. Radio telescopes can pick up the transmissions of cell phones and orbiting satellites. Signals from these sources can overpower anything that comes from beyond Earth. And the problem is only likely to get worse in the years ahead.
Astronomers do what they can to manage the problem. They place their radio telescopes in remote locations. They shield the receivers, and use computers to filter out interference from Earthly sources. They’re even considering placing telescopes on the far side of the Moon, where terrestrial signals would be blocked.
Still, there’s only so much they can do to protect their fragments of the radio spectrum.
Script by Damond Benningfield