Quelling concerns in the astronomy community, the world's largest radio observatory will not be drowned out by round-the-clock cell phone chitchat. Yesterday the National Astronomy and Ionosphere Center, which operates the Arecibo Radio Telescope in Puerto Rico, announced a pact with Motorola Inc. that allows NAIC access for 8 hours a day to a critical part of the radio spectrum.
Motorola plans to inaugurate a $5 billion global cellular phone service called Iridium this fall. The heart of Iridium--66 satellites, some of which are already orbiting Earth--will transmit phone calls at a frequency of about 1621 megahertz. However, some of the signal will spill over into bands used by radio telescopes, which are vastly more sensitive to weak interference than portable phones.
The agreement focuses on a narrow part of the radio spectrum, from 1610.6 to 1613.8 megahertz. At these frequencies, astronomers can detect charged molecules called hydroxyl radicals, which reveal, for instance, faint traces of comets and expanding shells around red giant stars.
The issue "represents a fundamental dispute about limited resources," says NAIC director Paul Goldsmith. And with more private satellite networks going up and more radio bands to worry about, astronomers will have to keep fighting to protect their access to radio waves. "We'll have to be as creative as we can to protect radio astronomy into the foreseeable future," says Michael Davis, a former director of the Arecibo observatory.