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CHINA IS well along in constructing the world’s largest radio telescope, scheduled to be completed in September 2016. Known as FAST, for 500-meter aperture spherical telescope, the project is making news for more than its enhancing mankind’s quest of extraterrestrial intelligence. It’s seen as a new space race, part of the People Republic of China’s goal of beating the west in matters hitherto largely American and European. Also, two major newspapers, The Guardian of Great Britain, February 16, 2016, and The New York Times, February 17, 2016, each played up that 9110 villagers in China’s remote Guizhou province are being uprooted because of the telescope’s construction.
Yes, but more than 15,000 people were displaced back in the 1930s, when the Tennessee Valley Authority disrupted a region of the U.S. by bringing it electricity.
The reason for the Chinese villagers’ relocation is technical, not political. Being a radio telescope, FAST senses a wide spectrum of electromagnetic radiation. It doesn’t depend on clear nights. What’s needed is isolation from modern society’s electronic babble. For this reason, FAST designers want a 5-km (3.1-mile) radius of the project to have a controlled environment of electromagnetic waves.
Like its smaller Arecibo Observatory counterpart west of San Juan, Puerto Rico, FAST makes use of local topography known as karst. The term comes from a Slavic word for barren, stony ground, typically of water-soluble limestone or dolomite with sinkholes and depressions called karst windows.
For FAST, one of these huge depressions is being lined with a mesh of cables forming a parabolic reflector of electromagnetic waves. The bigger the reflector, the weaker its detectable signal. The cool thing about a parabolic shape is its bouncing incoming parallel rays to a single point, its focus. Similarly, if the focal point emits electromagnetic energy, from a bulb, say, then the parabola bounces this light out in parallel rays.
Another way of detecting electromagnetic radiation, though not sending it, is the Karl G. Jansky Very Large Array in west-central New Mexico. The VLA’s 27 radio telescopes are each large, 25-meters/82-ft. in diameter, but nothing like the parabolas of Arecibo’s 305 meter/1000 ft. or FAST’s 500 meters/1640 ft. The VLA’s receivers are mounted on rails and function in unison along a giant Y, with a maximum collection area of 5.1 sq. mi./13.25 sq. km.
Years ago, when I lived in the Caribbean, I visited the Arecibo Observatory in Puerto Rico. It has been in operation since 1963, with 1974’s Arecibo Message being one of its attempts to communicate to a select portion of the universe.
The Arecibo Message collected several bits of humankind’s knowledge, including numbers 1 through 10 in binary form, atomic numbers of the elements forming DNA, a stick man and a hint of the Arecibo parabola. There have been no alien responses as yet. On the other hand, signals travel at the speed of light, and possible destinations are scads of light-years away.
On August 15, 1977, the Big Ear radio telescope of The Ohio State University, picked up what researchers deemed an oddity in a signal from the constellation Sagittarius. A clue to hydrogen, the most common element in the universe, was sufficient to generate a WOW! written on the data printout. The signal’s two measured frequencies were tantalizingly close to 1420.405…. Hz, precisely hydrogen’s spectral signature.
Nothing more came of WOW!, though on its 35th anniversary in 2012, Arecibo beamed a response containing 10,000 Twitter messages.
Somehow, the original Arecibo Message seemed a lot more indicative of intelligent life here on Earth. Y’know what I mean? ds
© Dennis Simanaitis, SimanaitisSays.com, 2016