Curious Iowa: Why does North Liberty have a radio telescope?

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North Liberty’s best kept secret looks like a giant satellite dish nestled in a wooded area between North Liberty and Coralville Lake. But it’s not a satellite. It’s a radio telescope that makes up one-tenth of an array that stretches from Hawaii to the Virgin Islands.

How did North Liberty, Iowa become the site for a radio telescope that is 82 feet in diameter? That’s what Curious Iowa, a series from The Gazette that answers readers’ questions about our state and how it works, set out to answer.

We spoke with Dr. Patricia Henning, Associate Director for New Mexico Operations at the National Radio Astronomy Observatory, to learn more about the giant piece of radio astronomy equipment in Eastern Iowans’ backyard.

What is a radio telescope and how did one end up in Iowa?

The electromagnetic spectrum is made up of various forms of electromagnetic radiation, from microwaves to X-rays and everything in between. Visible light — the light that our eyes can detect — makes up a small segment of the electromagnetic spectrum.

Most people are familiar with optical telescopes, which take in visible light. Radio telescopes collect radio waves, which are weakened by the time they reach earth. Radio telescopes focus and amplify radio light waves and make that data available for analysis.

“Physically, it’s all electromagnetic radiation, but the radio part shows us a kind of complementary picture of the universe to the optical and the other parts of the electromagnetic spectrum,” Dr. Henning told The Gazette.

The Very Long Baseline Array or VLBA is essentially a powerful, high-resolution radio camera made up of a network of 10 antennas.

“The longest baseline separation between dishes is over 8,600 kilometers, so it’s like a telescope 8,600 kilometers in diameter,” Henning said.

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Very Long Baseline Array Locations

Mauna Kea, Hawaii

Brewster, Washington

Owens Valley, California

North Liberty, Iowa

Hancock, New Hampshire

Kitt Peak, Arizona

Pie Town, New Mexico

Los Alamos, New Mexico

Fort Davis, Texas

St. Croix, Virgin Islands

Henning said the dish in North Liberty and the other nine dishes of the VLBA point at different parts of the sky.

“And that naturally occurring electromagnetic radiation, the radio waves, comes into the dish, and then we focus that to our detectors, to our receivers, and then the data at each dish is recorded independently.” Henning said.

Data, for the most part, is written on disks and then shipped to New Mexico where they’re combined electronically to make a radio picture.

The VLBA cost $85 million and came online in 1993. North Liberty is the only part of the array located in the Midwest. While some of the locations, like the two dishes in New Mexico, one in Arizona and one in Texas, are relatively close together, the Iowa, Washington state, and New Hampshire locations are spread out.

The Gazette previously reported that the University of Iowa played a large role in North Liberty becoming home to one-tenth of the VLBA. The UI was involved in earlier networks that used similar technology.

“And we do that because it makes a radio camera which is sensitive to angles on the sky in an optimal way,” Henning said. “So, Iowa is the right place to put one of our elements.”

The name “Very Long Baseline Array” is simplistic, but it does a great job describing what is does. The NRAO also operates the Very Large Array, which is 27 antennas located about 50 miles west of Socorro, New Mexico. The VLA’s signal runs on fiber optics to a super computer that combines the signals to make images.

Henning said the VLBA’s name denotes that the antennas are separated by large distances.

“The distance between any two antennas in an array is called the baseline.” Henning said. “And so, it actually has a lot of different baselines because it’s every pair … and so its claim to fame is that those distances are very long.”

What has the VLBA accomplished?

Recently, the VLBA has helped astronomers detect features at the edge of an active black hole located about 270 million light-years away in a galaxy located in the constellation Draco. That galaxy is known as 1ES 1927+654.

According to a Jan. 13 news release from NASA, “The features include the launch of a plasma jet moving at nearly one-third the speed of light and unusual, rapid X-ray fluctuations likely arising from near the very edge of the black hole.”

Radio images from June 2023 to May 2024 show the changing properties of the black hole. These observations may provide important clues as to why some, but not all, monster black holes produce plasma jets.

This is just one example of the cutting edge science the VLBA has accomplished in its 30 years of operation. Henning gave another example.

“There’s a binary black hole system that’s been discovered with the VLBA, so two supermassive black holes in one galaxy. It’s probably the merger of two galaxies that are very close together, I think it’s like 24 light-years apart.” Henning said. “I mean, it’s really incredible for supermassive black holes.”

“Now, you might be wondering, wait a minute, I thought we couldn’t see black holes. We can’t see the core in the middles of black holes, but we can see the glowing gas right around them. So that’s how we can detect that.”

Henning said “anybody with a great idea around the world” can submit proposals to compete for time to use the VLBA. Projects run remotely from New Mexico.

“You prepare the files that the telescope needs to run, and then they go in our queue and our operators select the projects that make the most sense for the telescopes at that time, and then you find out after the fact that you observed, and we get your data for you.” Henning said. “So it’s not quite as romantic as the old days.”

She remembers using the VLA as a student in the 1980s and being present when her project was being run. The new way, though, is “the best way to use these national resources,” Henning said.

The NRAO is a federally funded research and development center. It is a facility of the U.S. National Science Foundation and operated under cooperative agreement by Associated Universities, Inc., a nonprofit that manages the NRAO.

What will the VLBA look like in the future?

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The VLBA is 30 years old and VLA is 40 years old. Henning explained that while the systems are still “the best on the planet,” technology has improved since they were constructed. Enter the Next Generation VLA or ngVLA, which expands the wavelengths the equipment works at.

The name is a misnomer, Henning said, “because our plan is to have one big telescope across the U.S., which is a replacement, huge upgrade of capability over the VLA and VLBA, so they would act together.”

Combined, the VLA and VLBA have 37 antennas. The ngVLA would have 263 antennas. The proposed array would create a powerful “super telescope.”

Henning said that the ngVLA still is in the planning stages. The preliminary design work has been funded by the National Science Foundation for several years and a prototype antenna is being constructed in New Mexico. If you search “ngVLA webcam” online, you can see the progress that is being made.

Henning said that the antenna locations have not been finalized, but every revision of the plan includes antennas in North Liberty.

“So the current plan is, we love the VLBA antenna there, but what we really want to do is replace it with three more modern antennas,” Henning said.

If plans for the ngVLA come to fruition, the current VLBA antenna would be deconstructed, but it would be replaced. The ngVLA project is subject to funding.

“It’s a wonderful and unique telescope, very, very sharp images, but it all needs a major face-lift into the future.” Henning said.

In the meantime, the VLBA is undergoing upgrades to its back end software processing to make it more agile and sensitive.

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Comments: bailey.cichon@thegazette.com