Very Large Tourism

To get to the National Radio Telescope Observatory, you have to be committed.

Well, first, you have to be in New Mexico -- about an hour's drive south of Albuquerque, in the plains of San Augustin, to be precise, a Pleistocene lakebed bordered by the northern end of the Chihuahuan Desert and dotted with arid shrubs. Despite being some 6,970 feet above sea level, it feels like the basement of the world, wide and flat and under the massive Southwestern sky. Driving to the Observatory, the home of the famous "Very Large Array" of radio telescopes, is an exercise in patience. The repetitive landscape unfolds past the car windows at 80 miles an hour (the speed limit is 65, a Dadaist joke that no one seems to adhere to); with every rise you crest, you half-expect the fantastic vista to suddenly reveal itself, a sea of telescopes casting shadows on the parched Earth. For an hour, it doesn't.

After 50 miles on a two-lane highway, though, the payoff finally arrives: a colossal garden of 27 antennas the size of small houses dotting the desert like giant aluminum flowers. They couldn't look more out of place: they're extraterrestrial relics, futuristic Tiki gods, as grand and baffling as the Moai of Easter Island. Their technical operation is no less impressive. As a multi-purpose instrument, the telescopes of the Very Large Array can be configured four different ways; combined electronically, their data gives the resolution of an antenna 22 miles across, as sensitive as a dish 422 feet in diameter. The VLA, as it's called, has observed black holes and protoplanetary disks, sleuthed out Mercury's molten core, measured the speed of gravity, and probed the dark corners of the Universe. In 1989, it received radio communications from Voyager 2 as the spacecraft bolted past Neptune and into extrasolar space. And it, you know, starred in a certain Robert Zemeckis movie...

The scale of the desert plays with your sense of perspective as you pull up into parking lot abutting the visitor's center, a shoddy-looking building flanked by porta-potties. The dishes, which looked reasonable from the highway four miles away, seem actually preposterous from up close. They are huge. Blanched white, they all point in exactly the same direction: up.* Each dish is only a part of the larger system, and their synchronized operation is part of both their visual appeal and their usefulness to scientists. Whether scrunched together or arranged widely across the basin -- an effect not unlike a camera focusing and unfocusing -- together they can peer into the distant cosmos.

A hot desert wind blows everything not bolted down away. The displays in the Very Large Array's little on-site museum seem to be five years, maybe a decade, behind the times: one panel excitedly compares the storage capacity of the control center's magnetic tape to "a floppy disc on your PC." Outside of the visitor's center, a wind-and-sand-ravaged sign warns of poisonous snakes. This is the Wild West of astronomy.

Leaflets and poster boards at the VLA visitor's center repeatedly emphasize that these telescopes are not exclusively used for SETI research. "We don't look for little green men," the literature sneers. Still, telescope time has been lent out for SETI efforts occasionally -- most notably to double-check the "WOW!" signal in the mid-1990s. Thanks to the new Allen Telescope Array in Northern California, however, SETI won't need to poke around New Mexico for telescope access much longer: they'll have a large-scale telescope fully at their disposal (the SETI project there, once completed, will be able "see" transmissions from 1,000 light years away).

The Very Large Array self-guided walking tour is a half-mile loop peppered with chatty placards and bugs the size of oranges. At one stop, two white "whisper dishes" display the focusing properties of a parabolic dish, a classic kid's science trick. Further along, you can peek at the visiting scientists' quarters -- double-wides, basically -- and inspect the railway tracks by which the telescopes, with a special lifting locomotive, are picked up and moved to their various configurations, allowing "aperture synthesis interferometry with a maximum baseline of 22.3 miles." Everything else, including almost all of the antennae, is off limits, whichis fine -- it looks fantastic from a distance anyway.

*At least when I was there. Signs below the pedestrian-accessible 'scope indicated that the dishes might suddenly swivel all at once to follow some astronomical object, like rubber-necking spectators at Wimbledon. I was not privy to such a sight.

Supplemental Reading:

How Radio Telescopes Work, from the NRAO website

Contact, by Carl Sagan

Contact, the Robert Zemeckis film