The Very Large Array (that’s its real name) is a radio astronomy observatory in the plains of New Mexico made up of 27 enormous antennas. You may have seen it in the movie Contact or—less likely, perhaps—in the music video for Bon Jovi’s "Everyday." The VLA was built in the early 1970s to detect electromagnetic waves from space to help us better understand black holes, the Milky Way, and other astronomical phenomena.
But researchers from Ohio State have recently found that it could help us make important discoveries about what’s happening on Earth, namely, where people are testing nuclear bombs.
Dorota Grejner-Brzezinska, a professor of geodetic and geoinformation engineering at Ohio State, looked back at historical data gathered by the VLA and found that it contained disturbances caused by the nuclear tests in Nevada in 1992 and the North Korean test in 2009. These disturbances are caused by charged particles in Earth’s ionosphere that affect the signals the VLA picks up. "We’re talking about taking the error patterns—basically, the stuff we usually try to get rid of—and making something useful out of it," Grejner-Brzezinska said in a university press release.
Radio observatories like the VLA aren’t the only way of detecting a nuclear blast, of course. There are also seismic detectors and chemical sensors. In fact, GPS data can be used in a similar way as radio telescope data. But radio telescopes have a very high-resolution, and that may make them an important complement to the other techniques.
The more tools the better. According to Professor Joseph Cirincione of Ploughshares Fund, about half of the world’s nuclear material is protected by "little more than a chain link fence and a guard that works during the day."