Wednesday, January 28, 2009


As promised, today we shall re-visit the VLA. You may remember my amazement when I determined that the acronym was not representative of a collection of eight syllable words like most governmental gobbledygook. It is located about fifty miles west of Socorro, NM near Pie Town. It is huge! The “very large array” consists of radio telescopes of immense size (over eight stories) laid out in a “Y” over 22 miles of a scrubby high plain. There are 27 of these, 9 to a leg, in constant use in scanning the sky. They are not unlike the configuration of your dish for TV reception—aside from weighing 230 tons.

My first exposure to the VLA was just before sundown and I was prevented from further investigation or entry to the grounds. This trip, following US 60, was earlier in the day so I was able to really get a feel for the installation. The individual radio telescopes, with a dish 82’ wide, are capable of a resolution at its highest (43GHz) equivalent to seeing a golf ball at 100 miles. In a complex computer aided computation, triangulation of distances is possible with great accuracy along with the ability to locate objects otherwise unobserved. We have come a long way from two tin cans connected by a string.

The project, authorized by congress in 1972, and ready for use four years later cost $78,578.000, came in at budget and a year early. The bill came to roughly $1 per taxpayer. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.. There is a marvelous small Visitor’s Center on the grounds complete with a self guided walk among the various features.

To explain how these work, I shall rely upon a direct quote: “The VLA is an interferometer; this means that it operates by multiplying the data from each pair of telescopes together to form interference patterns. The structure of those interference patterns, and how they change with time as the earth rotates, reflect the structure of radio sources on the sky: we can take these patterns and use a mathematical technique called the Fourier transform to make maps.”

Speaking of maps: in the visitor’s center is an enlarged representation of a patch of sky which approximates the area that one might cover with the extended hand at arm’s length, which is so dense with various objects it defies counting. It is enlarged to about 24 sq. ft..

At ground level there is an impressive collection of interconnected railroad tracks for the express purpose of repositioning these telescopes. At 230 tons each, that is an operation which would be worth watching. In addition to the 27 largest units there are also various and sundry other smaller facilities which take advantage of the clarity of the mountain air—the facility is at an average of 6700’ elevation.

The most arresting aspect of this little adventure was the heightened awareness of how immense our universe is. Many of the dots mentioned on the map were representative of complete solar systems—some even far larger than ours. I am ever impressed by the vastness of God’s Creation and the puniness of man. What chutzpah to believe that we are in control. The delicate balance required to provide a suitable habitation for humans on this earth requires a driving force. I, having seen this, am all the more convinced of divinity in its creation.

In His abiding love,

Cecil Moon

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