Posted on 07/28/2002 8:47:30 PM PDT by Jedi Master Yoda
GREEN BANK, West Virginia (Reuters) - Welcome to the National Radio Quiet Zone. Feel free to shout, play the tuba or let out a primal scream. Just don't think about using a microwave oven.
One stray zap from a microwave -- or a car's sparkplugs, or even an electric blanket -- in the heart of the 13,000 square mile zone could interfere with science at the National Radio Astronomy Observatory at Green Bank, a patch of forested Appalachia just west of the Virginia border.
The quiet that the zone is meant to protect does not refer to sounds humans can hear; instead, it targets "noise" from human-made radio waves that might blot out the faint radio signals from distant stars, galaxies and pulsars.
The newest instrument at Green Bank is the biggest: a radio telescope so massive the Statue of Liberty, including the pedestal, could lie down on its blindingly white observing surface with room to spare. Its 43-story height and 16 million pound of tilting, turning mass make it the largest thing on land that moves.
This $79 million telescope is so sensitive, scientists worry that even the computers they use to monitor its workings could give off enough radiation to pollute the data.
Its control room, which has perhaps as many desktop computers as a small-town travel agency, located two miles from the telescope, has windows covered with copper mesh shades and doors as heavy as those on bank vaults to shield against radio interference.
RULES OF THE ZONE
Not many people stay at the zone's center in Pocahontas County, chosen in 1958 because it had the sparsest U.S. population density east of the Mississippi and the surrounding mountains serve as natural radio wave shields.
Those who live here, live by the rules of the zone.
This means, among other things, limited radio reception. Radio stations must turn their transmitters away from the big telescopes at Green Bank so as not to interfere with the instruments of the National Radio Astronomy Observatory.
Cell phone towers are virtually non-existent. Wireless microphones are forbidden. To get to the very middle of the installation, ordinary petrol-powered vehicles are banned. Observatory staff use a fleet of 1960s-vintage diesel taxis and pick-up trucks, with no sparkplugs or modern electronics.
"Interference is interference is interference, it doesn't matter where it comes from," said Wesley Sizemore, whose job it is to cut interference to a minimum in the Quiet Zone.
FM radio stations and television transmitters are fairly easy, Sizemore said in an interview; as long as they face away from the big telescopes, there is no problem. And satellites overhead are usually transmitting at different frequencies than those the scientists watch.
Garage-door openers and wireless microphones in the area close to the telescopes can be problematic. So can a bad thermostat, normal power lines or a heater's switch, Sizemore said. The most famous of the so-called unintentional radiators was an old dog's heating pad.
NASTY DOG'S HEATING PAD
Sizemore generally gets a laugh from the tale of how he tracked broadband interference to an elderly couple's home in the town of Green Bank, down the road from the observatory.
"They had a little dog outside in the dog house and the dog was rather old," Sizemore said, chuckling at the memory. "I like most dogs, but this was an exceptionally nasty little dog, so they had to kind of corral him while I chased the interference. But I tracked it down to their dog house."
The couple had given the dog an electric heating pad to lie on, but because the pad was not meant to be used this way, it became defective and gave off bursts of radio interference every few minutes, Sizemore said.
The solution was simple: the observatory got the dog a heating pad that was made to be used outdoors.
"It cost us maybe $50...We're sitting here operating a radio telescope that costs many hundreds or thousands of dollars an hour to operate and it was basically receiving garbage," Sizemore said. "So it's to our benefit and it's good for public relations. Fifty dollars well spent."
Some fixes are less basic. The nearby Snowshoe ski resort wanted to put in a wireless local area network for their computers, but decided to hard-wire the network instead to avoid interference.
SEEING THROUGH COSMIC DUST
There are other radio telescopes around the world -- one huge installation is the Very Large Array in New Mexico, another is Arecibo in Puerto Rico -- but scientists believe Green Bank's big new telescope will be especially sensitive to incoming cosmic signals.
Officially named for Robert C. Byrd, the veteran senator famed for bringing federal dollars to West Virginia, the new instrument is called simply GBT by astronomers, short for Green Bank Telescope.
"The GBT will be such an enormous leap in sensitivity...a leap by factors of 10, which means a factor of 100 in observing time," telescope scientist Jay Lockman said in an interview. "So things which took many hours to detect could be detected in seconds."
When most people think of telescopes, they think of instruments that look at the universe in waves of light. While these can produce startling and beautiful images, they cannot see through the dust and gas of the cosmos, as radio telescopes can.
One famous image made by the orbiting Hubble Space Telescope ( news - web sites) shows a star-birth chamber known as the Pillars of Creation. Optical telescopes can only see the chamber; radio telescopes can see inside it, Lockman said.
"The action is all inside," Lockman said. "We can see that there are new stars being born in there, but Hubble will never see it in a million years." He paused. "Well, maybe in a million years, but only because the stars will have blown away the dust."
LOUDEST PLACE IN QUIET ZONE
Ironically, one of the loudest places in the Quiet Zone is in the receiver room at the top of the GBT. This is where incoming radio waves that have been sensed by the big telescope's observing surface are channelled into computers to be processed.
Ascent to the telescope's surface, which catches the incoming cosmic radio waves, is done via a short flight of steps, an elevator and a long catwalk. From there, another elevator goes up along a slanted track to the instrument's towering sub-reflector, which bounces the radio waves down into the reflector room.
A gentle chirping can be heard just outside the receiver room, but step inside and the chirp escalates to a rhythmic mechanical shriek. This is the sound of dewars, machines that remove as much of the atmosphere as possible from the pipeline that carries incoming radio waves to computers to be analyzed.
They are also supposed to not be transmitting, but people who drive near the VLA or around the Nevada (Mercury,NV)(Rachel,NV) facilities often report hearing them transmitting at extreme power in a broadband, screaming at the universe for hours on end. What are they saying?
Such a transmission would serve little purpose unless the desired recipients were light-years away at least. Transmissions are said to be particularly loud and heavy when the dishes are broadcasting off just barely over the northern horizon.
"Strela's Tesla Coils To Go"
West Virginia PINGS )))))))
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.