The
name says it all -- it's a very large array of radio
antennae resting 2,124 meters above sea level in the
desert of New Mexico. It has been the used in countless
television shows, commercials, and science fiction
films. A modern marvel utilizing the best physics
and engineering of the time to create something that
functions larger than it actually is. Strictly speaking,
the VLA isn't an antenna, it's an interferometer.
That means it uses physics to combine the signals
of all 27 dishes into a single signal that looks as
if it were received by a dish as large as the distance
between all 27 dishes. The overall size of the array
can be changed at will because the dishes are arranged
on tracks, similar to railroad cars, going in three
different directions in roughly a "Y" shape. At its
smallest, the array is one kilometer in diameter,
but can be expanded to a maximum of 36 kilometers.
Each of the antennae are 25 meters in diameter and
weigh 230 tons. The VLA is operated by Associated
Universities, Incorporated for the National Science
Foundation as the National Radio Astronomy Observatory.
It's mostly used for radio astronomy on the P, L,
C, X, U, K, and Q bands (300-50,000 MHz). But it is
occasionally used for tracking satellites and studying
the weather. At its most sensitive, it can see a golf
ball 100 miles away, but that's not a very good way
to get them to notice you. A better way is to knock
on their door. Directions are on their web site. The
public is welcome.
