Interference and Radioastronomy

Radioastronomy began in 1933 with Karl Jansky's accidental discovery of radio emission from the center of the Galaxy as he was studying the effect of thunderstorms on transatlantic telecommunications. Six decades later, telecommunications and other radio services are threatening the future of radioastronomy. Whether searching for the signature of a protogalaxy, studying the maseremission signposts of star formation or pursuing answers to any of the myriad questions of modern astrophysics, today's radioastronomer is often frustrated by man-made radio interference. From satellites, radar, radio and television transmitters, and wireless personal communication systems of all sorts to microwave ovens, computers and even garage door openers, the same technology that lets us study the universe at radio wavelengths is producing a flood of man-made signals. Figure 1 illustrates how noisy the radio spectrum has become at wavelengths around 1 meter. (The remedy offered in the figure is, alas, just an astronomer's fantasy.)