LISTENING TO THE COSMOS
GIANTS IN THE DESERT
Fifty miles west of Socorro, New Mexico, on the Plains of San Agustin, twenty-seven radio telescope antennas stand in formation across the high desert. Each dish spans 82 feet in diameter and weighs 230 tons yet moves with precision to track cosmic radio signals traveling billions of years through space. This is the Karl G. Jansky Very Large Array, operated by the National Radio Astronomy Observatory, and it represents one of humanity's most ambitious attempts to see the invisible universe.
ENGINEERING AT SCALE
Just last week I
stood beneath one of these antennas revealing the remarkable engineering
required to make radio astronomy work. The massive dish surface must maintain
its parabolic shape to within a fraction of a wavelength while tracking objects
as they move across the sky. Each antenna can be repositioned along railroad
tracks in a Y-shaped configuration, allowing astronomers to adjust the array's
effective size depending on their observational needs—compact for wide-field
surveys, extended for high-resolution imaging.
The site itself was chosen carefully. The San Agustin Plains sit at 7,000 feet elevation, surrounded by mountains that help shield the sensitive receivers from human-generated radio interference. The high desert climate provides clear skies and stable atmospheric conditions. From the visitor center overlook, you can see antennas scattered across the landscape, their white surfaces stark against the brown plains and distant peaks—a visual reminder of the scale required to observe the cosmos.
SEEING THE
INVISIBLE
Radio astronomy reveals a universe fundamentally different from what our eyes can see. When we look at the night sky, we observe only visible light—a narrow slice of the electromagnetic spectrum. But the universe produces radiation across the entire spectrum, from low-energy radio waves through microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays. Earth's atmosphere blocks most of this radiation, which is fortunate for life but limiting for astronomy. Radio waves, however, pass through the atmosphere, making ground-based radio telescopes possible.
The interpretive
displays at the VLA help visitors understand this invisible realm. Radio waves
from space aren't fundamentally different from the ones carrying cell phone
signals—they're just produced by wildly different sources and carry information
about exotic physics. A galaxy collision generates radio emission as matter
spirals into supermassive black holes. Supernova remnants glow in radio
wavelengths as shock waves energize the surrounding gas. Regions where new
stars are forming emit radio waves from ionized hydrogen and complex molecules.
DISCOVERIES
AND IMPACT
Since beginning
operations in 1980, the VLA has contributed to groundbreaking discoveries
across astrophysics. It has mapped the structure of nearby galaxies, revealed
planets forming around distant stars, discovered ice on Mercury, tracked
asteroids that might threaten Earth, and helped establish the existence of
supermassive black holes at the centers of galaxies. VLA observations have
contributed to two Nobel Prizes in Physics.
The facility
underwent a major upgrade between 2001 and 2012, replacing its electronics and
correlator system while keeping the iconic antennas. This transformation
increased sensitivity tenfold and greatly expanded the range of observable
frequencies. Today's VLA can observe from 1 to 50 gigahertz, covering
wavelengths from 6 meters down to 7 millimeters.
A LIVING
FACILITY
The VLA isn't a museum—it's an active research facility operating 24 hours a day, 365 days a year. During any visit, maintenance crews might be servicing antennas, technicians monitoring operations from the control building, or astronomers around the world receiving data from their allocated observation time. The massive antennas periodically roll along their tracks to new positions, a reconfiguration process that takes about a week and occurs four times per year.
The visitor center welcomes the public
daily and offers a self-guided walking tour. You can stand beneath a full-scale
antenna, examine the receivers that detect faint cosmic signals, and explore
exhibits explaining radio astronomy. A short film introduces visitors to the
science, and the gift shop features books, posters, and educational materials.
LOCATION AND ACCESS
The VLA lies approximately 50 miles west of Socorro, New Mexico, accessible via US Highway 60. The remote location—essential for radio astronomy—means visitors should plan accordingly. The nearest services are in Magdalena (27 miles west) or Socorro. The site sits on a high desert plain with limited shade, intense sun at altitude, and weather that can change rapidly. But the isolation is part of the experience. When you stand among these instruments under the vast New Mexico sky, you're at one of the places where humanity listens most intently to the cosmos.
For more
information: Visit the Very Large
Array – National Radio Astronomy Observatory | Visitor Center: (575)
835-7000
The Karl G.
Jansky Very Large Array is a facility of the National Radio Astronomy
Observatory, operated by Associated Universities, Inc., under cooperative
agreement with the National Science Foundation.
Written and modified with Anthropic's Claude.
Photographs by the Author.
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