Nepedia
Back to Discover
Advanced Reader
🚀

Very Large Array

space Maturity 11-13 Next article →

The Karl G. Jansky Very Large Array (VLA) is a massive radio astronomy observatory. It is located on the Plains of San Agustin in central New Mexico. This site sits between the towns of Magdalena and Datil. The VLA is a centimeter-wavelength observatory, meaning it studies radio waves with specific lengths. It is a vital tool for understanding the physical universe. The array allows scientists to study objects that do not emit visible light.

Bracewell Sundial
Bracewell Sundial

The VLA functions through a process called aperture synthesis interferometry. The array consists of 28 radio telescopes arranged in a Y-shaped configuration. Currently, 27 antennas are operational while one undergoes maintenance. These antennas are mounted on double parallel railroad tracks. A specialized locomotive named "Hein's Trein" moves the dishes to different positions. By changing the distance between the antennas, the array acts like a single antenna with a variable diameter. This allows astronomers to balance angular resolution and surface brightness sensitivity. The system can create up to 351 independent baselines to capture data.

Image Release the ngVLA Prototype Handover Ceremony
Image Release the ngVLA Prototype Handover Ceremony

Astronomers use different configurations to change how the array views the sky. There are four common configurations labeled A through D. Configuration A is the largest, while Configuration D is the tightest. In Configuration D, all dishes are within 1 kilometer of the center point. The observatory typically cycles through these various setups every 16 months. The antennas themselves are moved every three to four months. To improve imaging of northern or southern sources, the moves to smaller configurations happen in two stages. First, the east and west arms are shortened. Later, the north arm is shortened.

The history of the VLA began with the leadership of David S. Heeschen. He guided the development of the observatory for sixteen years. The United States Congress approved the project in August 1972. Construction started six months later, and the first antenna arrived in September 1975. The complex was formally inaugurated in 1980. The total investment was $500 million, which is equivalent to about $2.1 billion in 2020 dollars. In 2001, an upgrade project called the Expanded Very Large Array (EVLA) began. This project replaced 1970s electronics with modern hardware. It was completed in 2012, and the facility was renamed the Karl G. Jansky Very Large Array to honor a scientist.

Image Release the ngVLA Prototype Handover Ceremony
Image Release the ngVLA Prototype Handover Ceremony

The VLA has been used for many significant scientific discoveries. In 1989, it received radio communications from the Voyager 2 spacecraft during its flyby of Neptune. Scientists use the VLA to observe black holes and protoplanetary disks around young stars. It has also traced complex gas motions at the center of the Milky Way. The VLA Sky Survey (VLASS) is another major project. This survey aims to cover 80% of the sky visible to the VLA. Scientists expect to find approximately 10 million new objects through this survey. This would be four times more objects than are currently known.

Bracewell Sundial
Bracewell Sundial

Looking toward the future, the National Radio Astronomy Observatory announced a new project. This project will transform the site into the Next Generation Very Large Array (ngVLA). This upgrade will replace the aging antennas with more than 260 new ones. The new system will include a Short Baseline Array, a Main Interferometric Array, and a Long Baseline Array. The ngVLA is expected to be ten times more sensitive than the current VLA. Construction for this upgrade is estimated to cost about $2 billion. Early science operations for the ngVLA are expected to begin in mid-2031.

Image Release the ngVLA Prototype Handover Ceremony
Image Release the ngVLA Prototype Handover Ceremony

Visitors can explore the observatory through a dedicated visitor center. The center includes a museum, a theater, and a gift shop. A self-guided walking tour allows people to see the equipment in the high desert. One notable feature is the Bracewell Radio Sundial.

Bracewell Sundial
Bracewell Sundial

This sundial uses a central sphere to cast shadows that mark the time of year. It also marks the positions of radio sources like Cygnus A and Cassiopeia A. This site connects the public to the complex work of radio astronomy.

659 words

Where will your curiosity go next?

Keep exploring at your chosen reading level.

🖼️ Images & Media (3)
File:Plant ecologies on site.jpg
Plant ecologies on site.jpg
File:Image Release the ngVLA Prototype Handover Ceremony.png
Image Release the ngVLA Prototype...
File:Bracewell Sundial.jpg
Bracewell Sundial.jpg
More to explore

What is Nepedia?

A free, ad-free encyclopedia for children. Every article is written at five reading levels, so the same page works for a five-year-old and a fifteen-year-old — use the level switcher above to see this one change. No account needed to read.