Eavesdropping on The Sounds of Silence
The Plains of San Agustin are expansive, stretching 55-miles northeast to southwest, ranging from 5 to 15 miles across. Highway 60 crosses the plains, a lonely asphalt ribbon running east to west. Rugged mountains surround the plains, serving as distant beacons on the long, empty road between Magdalena and Datil. There are more cows than humans in the area, with occasional dusty roads running like veins to a solitary house in the distance.
The mountain ranges surrounding the Plains of San Agustin create a natural, impenetrable stone fortress. They shelter the central valley from radio transmissions emanating from distant cities, like Albuquerque and Socorro. The remote, isolated location is ideal for radio astronomy. Listening to the faint radio waves transmitted by the universe requires silencing the deluge of radio transmissions emitted from Earth. Additionally, climate is an important consideration. Humidity impedes radio astronomy, because water molecules distort the radio waves passing through them. Also, they give off their own radio waves, which interferes with observations at certain frequencies. Fortunately, water molecules don’t last long in the high desert, making the Plains of San Agustin the ideal site for the Very Large Array, aka the VLA.
Very Large Array, aka VLA
The Karl G. Jansky Very Large Array, commonly known as the VLA, is one of the world’s premier astronomical radio observatories. It is a multi-purpose tool designed to study astronomical objects. The complex consists of a collection of 27 radio telescopes, placed in a Y-shaped configuration. Each antenna is 82 feet diameter. VLA staff move the individual dishes into four standard arrangements on a three month rotation. The different alignments provide astronomers with varying levels of detail and sensitivity.
The VLA allows astronomers to eavesdrop on the galaxy, gathering details about stars dying in supernova and hypernova explosions, structures inside giant clouds of gas and dust, where stars might be forming, and activity around the immense black hole at the center of the Milky Way Galaxy. Each antenna observes radio waves and light waves emitted by distant celestial objects. Then, computers integrate the data gathered from the dishes, generating high resolution images comparable to that of a massive single dish telescope, 22-miles in diameter. Overall, the VLA’s maximum angular resolution is better than a tenth of an arc second, which is comparable to the Hubble Space Telescope at optical wavelengths.
Astronomers have used the VLA to study radio galaxies, quasars, pulsars, supernova remnants, gamma-ray bursts, radio-emitting stars, the sun and planets, astrophysical masers, and black holes.
Astronomers at the National Radio Astronomy Observatory (NRAO) knew in the early 1960’s that an array of radio dishes would rapidly advance the research being done with giant, single-dish telescopes. Fortunately, they secured funding from Congress in the fall of 1972, breaking ground early in 1973. They placed the first antenna in September, 1975. The dream culminated in 1980 when the facility officially opened. At the time, it was the largest configuration of radio telescopes in the world.
The array was renamed in January, 2012, lengthening the name to the “Karl G. Jansky Very Large Array.” Considered one of the founding figures of radio astronomy, Karl Guthe Jansky was an American physicist and radio engineer who detected radio waves emanating from the Milky Way in 1931. Whereas I appreciate the effort to honor a pioneer of radio astronomy, I prefer the shorthand moniker…VLA.
Though the VLA is primarily a tool for astronomers around the world, it has been used for research beyond astronomy, including atmospheric/weather studies and satellite tracking. Overall, American taxpayers have gotten a significant return on the 78.5 million dollar investment, with significant contributions to space science and astronomy, including…
- NASA used the VLA to listen to transmissions from the Voyager 2 spacecraft as it flew past Neptune in 1989.
- The VLA was used to search the galaxies M31 and M32 from December 2014 – January 2015. They surveyed trillions of systems for powerful signals emitted from advanced civilizations.
- The VLA Sky Survey (VLASS) began in September, 2017. The survey will perform three full scans of the sky visible to the VLA, encompassing 80% of the Earth’s sky. Astronomers hope to find up to 10 million new objects with the survey, which would be four times more than what they know about now.
The SETI Institute and the NRAO announced a collaboration on February 14, 2020, bringing SETI technology to the VLA. The collaboration is a mouthful: the Commensal Open-Source Multimode Interferometer Cluster Search for Extraterrestrial Intelligence (COSMIC SETI). Basically, they upgraded the computing systems and networks to increase the power and precision of the antennas. Ultimately, the partnership entails the ongoing search for life in the universe. The giant dishes on the plains are searching the heavens for events or structures indicative of life, like structures built around stars, constructed satellites, or atmospheric chemicals associated with industrial pollutants. Additionally, the tech upgrades will allow the VLA to explore other natural astrophysical phenomena in new ways.
Pop Culture References
The VLA looks like something from a sci-fi novel. Thus, it should come as no surprise that the site has been featured in several films with an offworld theme. Many people remember the VLA from the 1997 movie Contact, starring Jodie Foster. The VLA was the site of first contact with aliens. However, film buffs might recognize the distinctive dishes in scenes from the 1984 movie 2010: The Year We Make Contact and the 2009 Terminator sequel, Terminator Salvation.
Visiting the VLA
Old Highway 60 Socorro
Socorro, New Mexico 87825
The VLA site is open from 8:30 AM to sunset year around. There is a small museum, theater, and gift shop at the visitor center. The gift shop closes on Thanksgiving, Christmas Eve, Christmas Day, New Year’s Eve and New Year’s Day.
They offer two types of tours. Self-guided and Guided. Both cost $6 ($5 for AAA and veterans).
- Self-guided, walking tours are available every day during operating hours. There are kiosks with information about the Observatory. Pets allowed on the walking tours.
- Additionally, they host guided tours on the first and third Saturday of each month at 11am, 1pm, and 3pm. No reservations required. Show up at the VLA Visitor Center 15 minutes before the tour. Generally, the tours take about 50 minutes.