Machines Drown Out Whispers From Space : Astronomers Bugged by All That Noise

WASHINGTON — Electromagnetic clatter from millions of man-made sources is drowning out whispers from the heavens and crippling research by radio astronomers who probe distant stars, scientists say.

Marcus Price, a radio astronomer at the University of New Mexico, says the machines of modern America--from car engines to computers to automatic garage door openers--are helping to pollute the airwaves with electromagnetic garbage.

“The radio spectrum is a natural resource and, as with any natural resource, it can get polluted,” Price said in an interview while attending an astronomy conference Monday. “It’s not like air or water pollution because you can’t see it, but it’s there.”

For that reason, he said, astronomers are anxious that unnecessary uses of radio signals be eliminated. In many cases, gross radio interference sources could be controlled with the use of filters or shields that would add only a dollar or two to manufacturing costs, he said.

‘Vital Part of Life’

“The radio spectrum is a vital part of our everyday life,” said Price. “Every time you order a pizza or call for an ambulance, it’s probably radio dispatched and there’s another signal. That’s why we worry about this limited resource being used for frivolous purposes.”

Electromagnetic gridlock is only one type of pollution affecting astronomers. At a meeting this week sponsored by the International Astronomical Union, astronomers from around the world said their work also is hampered by man-made light, and by debris left in space that reflects sunlight and causes streaks on astronomy photographs.

For radio astronomers, the electromagnetic spectrum can help unlock secrets of star formation millions of light-years away. Each type of molecule, when excited by heat, puts out a unique radio signal. By capturing and analyzing these signals, radio astronomers can determine the chemical composition of processes taking place at points in the universe not even visible to optical telescopes.

This work has defined the shape of Earth’s home galaxy, discovered key components in the lives of stars and confirmed formation of complex chemicals within galaxies and stars.

Radio astronomers explore virtually every portion of the spectrum to catch the faint, distant star symphony, but Price said continuation of this work is threatened by the sudden rise of man-made radio signals.

“In the last five years, we’ve seen an explosion of use of the radio spectrum for consumer devices,” he said.

Environmental Shielding

Many of these signals could be shielded from the environment.

Spark plugs in automobiles, for instance, he said, create a slight radio signal every time they fire. This could be corrected for about $2 per vehicle, Price said.

Cellular telephones, computers, hand-held calculators and electronic toys all add to the clutter, he said, and all could be filtered and shielded for small cost.

Price said radar signals used for defense, air traffic control and even highway speed-checking guns all put out signals in portions of the spectrum important to astronomy. So do television stations.

A new Soviet navigation system is threatening to blot out study of the hydroxyl radical, a key part of the chemistry of water and of some organic chemicals. Research on this molecule could give important clues to the existence of life beyond the Earth.

Radio astronomers are able to detect the hydroxyl radical at 1600 to 1700 megahertz on the spectrum. A system of navigation satellites now being deployed by the Soviet Union would operate constantly in this same portion of the radio band.

“It is impossible to study this molecule when they (the satellites) are above your horizon,” he said. The strong Soviet navigation signal simply blots out everything else in that portion of the spectrum, said Price.

FCC Help Sought

“Eventually, the navigation system will cover the whole Earth and we could lose the ability to study the hydroxyl radical,” he said. “This robs you of considerable information.”

Price said astronomers recognize that little can be done to control the growing use of the spectrum for important services such as aircraft control and communications. But the scientists hope that the Federal Communications Commission and the world community will take measures to control the “unnecessary and frivolous use of a diminishing resource.”

And, Price said, astronomers recognize that eventually they’ll have to leave the Earth and its cacophony of electronic noise, if they are to continue studying the dim electronic voice of the universe. But where would they go?

“The backside of the moon has been designated as a quiet zone,” he said. “It would be shielded against the signals from Earth. That’s about our only choice.”