Wednesday, July 1, 2009

The Very Large Array


The Boychick is hosting his cousin D., in from Illinois for a two-week visit.
The first week was a tour of the skate parks of the Greater Albuquerque area, but at the beginning of the second week the Engineering Geek and I decided that, not to be outdone by Camp Aunt Madge, we needed to take at least one educational field trip somewhere else in New Mexico.

The guys said a decided "No" to Fanta Se and the museums, Old Town, or the Salinas National Monument. But they said "Okay" to the Very Large Array, which is officially part of the National Radio Astronomy Observatory. Featured in many films, it was the setting for much of the action in the movie based on Carl Sagan's novel, Contact. I don't know if it was the big machines or the movie that hooked them, but off we went on a jaunt to to the Plains of San Augustin, where the radio telescopes are.

I insisted that we take the back roads, South NM 14 to Mountain Air, and then U.S. 60 to Bernardo and Socorro, Magdalena and the VLA. Here is a view looking south to Chupadera Mesa from Torreon, NM. Chupadera blocked any outlet of Glacial Lake Estancia into the ancenstral Rio Grande, creating salt flats as blow-out dunes. But we were headed for the other big, ancient lake bed in West-Central New Mexico.

A view of the two arms of the VLA from the photo stop on US 60. What is amazing is that each of the dishes is the diameter of a major league baseball diamond, but here they are, almost lost in the immensity of the Plains of San Augustin, an old glacial lake-bed.

Three radio recievers pointing to the eastern sky. The foreground shows a blow-out dune of lake sand and silt, deposited here more than 10,000 years ago, during the Pluvial (wet, lake) period of the Wisconsin glaciation.

And the politicians think they discovered global climate change?

The guys walk and discuss whether or not the radio receivers could be made into senders, in order to make contact with whatever might be "out there."

This summer, the receivers are in the "C" position, the axis of the Y formation being pretty short. This gives them more resolution for detail, but a narrower "view" of the part of the sky they are "looking" at. Here one receiver is "looking" at a different point than the other two.

The radio signals are a portion of the electromagnetic spectrum that we are accustomed to "listening" to, but computers make images of the radio sources, using color to show doppler shifts created by movement.

Each receiver has four orienting/tracking motors, and its own air-conditioning unit to keep the temperature low, which filters out earth-based "noise" in order to better received the faint radio signals from space. Standing under them, one can the faint hum of the tracking motors that keep the receiver oriented to a fixed point in the sky as the earth turns them toward the west.

They are huge, and yet gracefully beautiful in proportion to the vastness of the Plains of San Augustin.

The axes of the Y configuration in the the most outstreached "A" form, would cross the whole Washington, D.C. metropolitan area, stretching in Virginia, Mayland and Pennsylvania. But that is not the logest axis. The VLA is part of a continent wide Very Long Baseline Array, 3,000 miles long. You can "see" detail from very far away with the VLBA.

And of course, the farther out you look, the further back in time you see. One image captured at the VLA showed Quasars 10 billion light years away. The light left them 10 billion years ago. Before the sun was born, and the earth was formed. Space-time is inconceivably immense. And growing bigger every second . . .

What great vision our technology gives us . . .


Mark said...

The VLA has always been an 11 on the awesome scale. Amazing how we can use such a system to peer to the very edge of the Universe.

After we visited the site some years ago, I saw "Contact" for the first time. The movie was partially filmed at the VLA and I had fun going, "saw that, been there, recognize that guy," etc. :-)

Greg Smith said...

You might also mention that the entire area around the VLA is radio silence (no cell phone reception) and they ask you to turn off your cells and other radio equipment before approaching the arrays.

Elisheva Hannah Levin said...

Greg: I knew they asked you to turn off radio sources and I knew we got no cell reception on site, but we also had no cell reception until we were on the hill back into Socorro. I thought it was my service provider. I did see a microwave repeater tower in Magdalena. How big is the radio silence bubble? How does that effect sort of nearby towns like Magdalena?
Consider it said.