Wednesday – April 29, 2015
National Radio Astronomy Observatory
Socorro, New Mexico
We visited the Very Large Array (VLA) this morning. It is run by the National Radio Astronomy Observatory and is located on U.S. Highway 60, fifty miles west of Socorro, New Mexico.
The VLA is a powerful telescope that observes the Universe, night and day. There are 27 dish-shaped antennas tuned to a kind of light that the eyes cannot see. This invisible light is in the form of radio waves. Visible light, the light our eyes and optical telescopes can see, is only a tiny fraction of the light given off by normal matter in the Universe.
Radio waves reveal previously unseen activities of stars, galaxies, and planets and map the chemical workings of the gas and dust clouds that create them. Optical telescopes cannot see into these places, because those same clouds block their view.
Unhindered, radio waves can travel for billions of years across the vastness of space. They provide the VLA with the data that help astronomers construct a timeline of the Universe – from its ancient past to its possible future.
Each of the 27 white dishes of the VLA gathers faint, natural radio waves traveling through distant space from objects such as galaxies, black holes, and baby stars.
Each of the VLA dishes is actually larger than the biggest optical telescope in the world. However, a single VLA antenna cannot see as clearly as its optical cousin. Why is that? Bigger telescopes do reveal finer detail, what astronomers refer to as having greater "resolving power." But radio waves are much longer than light waves, so a much bigger telescope is needed to resolve finer details. A radio telescope needs to be many miles across to rival the resolving power of an optical telescope. It is not possible to build one dish that big, but the connected array of 27 large antennas of the VLA create a telescope that is 22 miles in diameter!
Each of the 27 antennas in the array weighs over 230-tons, is 82 feet across and over 90 feet high. Motorized drives steer these 100-ton white dishes around, dip them up and down, and keep them pointed exactly on the cosmic radio source for several hours at a time to collect enough radio waves from each object they observe.
The array of 27 radio antennas spans a huge "Y" shape (called the Wye). Every four months the antennas are moved to different stations along each arm of the Wye. At its most compact configuration, the array has a wider field of view and maximum sensitivity to diffuse gas. At its most extended, the array zooms in on finer detail. Unique Transporters carefully lift and relocate the 230-ton antennas to one of 72 new positions along the "Y" shaped railroad tracks.
Since the VLA first began watching the skies back in 1976, it has observed nearly 43,000 different cosmic objects.
The Warner Brothers Movie "Contact," based on Carl Sagan’s novel, was filmed in part at the VLA. In September 1996, film makers and actors arrived at VLA to film many of the scenes in the movie. About 200 people from the "Contract" crew worked here during five days of fast-paced activity. A movie "base camp" was set up behind the Antenna Assembly Building, where equipment and wardrobe trailers, a kitchen trailer and a large dining tent were located. House trailers sat in the Visitors Center parking lot for leading actress Jodie Foster, director Robert Zemeckis and producer Steve Starkey.
At the Visitor Center, visitors can take a self-guided tour to a radio dish antenna and view a 23-minute movie – Beyond The Visible (The Story of the Very Large Array) – narrated by the actress Jodi Foster.
Tomorrow another adventure begins.