NWA-PCUG Newsletter Article, July 2011
Electronic Ears
By Berry F. Phillips,
a member of the Computer Club of Oklahoma City
September 2010 issue of The Monitor
bfpdata(at)1access.net (click to email author)

For many, the science fiction movie, Contact in 1997 starring Jodie Foster and adapted from a book by Carl Sagan by the same name, was their first introduction to SETI Institute for Extra Terrestrial Intelligence) and the largest electronic ear in the world. The Arecibo Observatory, featured in Contact, is the world's largest and most sensitive radio telescope with a dish at nearly 1000 feet across which is located in northwestern Puerto Rico. SETI would use this electronic ear to listen to sounds from outer space which was processed on several thousand volunteer personal computers in their search for alien civilizations. Today SETTI Institute uses the newly developed Paul Allen Array (ATA) which was a joint project with the Radio Astronomy Laboratory at the University of California, Berkeley located 290 miles northeast of San Francisco, California at the Hatcreek Radio Observatory. The first phase of the of the ATA was completed and operational with 42 smaller dishes linked together on October 11, 2007, which was funded by Paul Allen, one of the cofounders of Microsoft Corporation. This Large Number Small Diameter (LSND) is less expensive to build than the large dish and when fully developed to 350 six meter dishes will offer even greater search capabilities than the single dish design. Mr. Allen has contributed over thirty million to the project through the Paul Allen Foundation. Additional funding for the development of additional phases is currently being sought from a variety of sources.

Electronic ears are radio telescopes in the form of directional radio antennas used in radio astronomy. They are often used in tracking and collecting data from satellites and space probes. They differ from optical telescopes in that they operate in the radio frequency portion of the electromagnetic spectrum where they collect data on radio sources. Radio telescopes are typically large parabolic ("dish") antennas used singly or in an array. These observatories are preferentially located far from major centers of population and often located in valleys to shield them from electromagnetic interference (EM).

The world's largest full dish as mentioned previously is the Arecibo radio telescope which while fixed in the ground is steerable by means of a moving receiver. The largest individual radio telescope of any kind is the RATAN-600 located near Nichny Arkhyz, Russia which consists of a 576-meter circle of rectangular radio reflectors, each of which can be pointed towards a conical receiver. The largest radio telescope in Europe is the 100-meter diameter antenna in Effelsber, Germany which also was the world's largest fully steerable telescope for 30 years until the slightly larger Green Bank Telescope was opened in West Virginia, United States, in 2000. The third-largest fully-steerable radio telescope is the 76-metre Lovell Telescope at Jodrell Bank Observatory in Chesire, England. China officially started construction of the world's largest single-aperture radio telescope in 2009, the FAST with a dish area as large as 30 football fields which will stand in a region of typical Karst depressions in Guichou and will be finished in 2013.

There are numerous operational radio telescopes of different sizes around the world. European astronomers have created a high speed network of 16 radio telescopes from six continents at one source in space combining observational signals. This virtual telescope delivers better resolution than any single telescope on earth. The linkage combines 16 radio telescopes from six continents via a high speed network which makes it easier to react to so-called targets of opportunity-transient events such as supernova explosions and gamma-ray boasts in space.

The very latest development is that the first major radio telescope, for many decades, will be built in Britain and will listen to the sky at FM frequencies, providing vast quantities of data to a supercomputer in Holland, paving the way for unexpected new discoveries.

Giant electronic ears are listening all over the world for alien civilizations and so much more as we attempt to unravel the mysteries of the universe. What was once called science fiction is becoming science reality in the ever evolving technical world of radio astronomy. Stay tuned!

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