Radio telescopes can spot nuclear activity.

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In the search for rogue nukes, researchers have discovered an unlikely tool: astronomical radio telescopes. Researchers at Ohio State University, Columbus, previously demonstrated another unlikely tool, when they showed that south Korean GPS stations detected telltale atmospheric disturbances from North Korea's 2009 nuclear test. Both techniques were 10om out of the discovery that underground nuclear explosions leave their mark on the outer reaches of Earth's atmosphere.

Now, working with astronomers at the Naval Research Laboratory (NRL), Washington, D.C., they have analyzed historical data from the Very Large Array (VLA), a constellation of 27 radio telescopes near Socorro, N.M., and discovered that VLA recorded a very similar pattern of disturbances during the last two American underground nuclear tests, which took place in Nevada in 1992.

Dorota Grejner-Brzezinska, professor of geodetic and geoinformation engineering, says the new findings help support the notion that GPS systems, and their technological successors, global navigation satellite systems (GNSS), are viable tools for detecting clandestine nuclear tests around the globe.

"With a global availability of permanently tracking GPS networks now extending to GNSS, a really tremendous amount of information...