IT COULD soon become much easier to detect underground bunkers or sinkholes,
say researchers in Massachusetts. The trick is to measure variations in the
gravitational field.
For decades, variations in gravity have been used to ferret out underground
structures. The gravitational force should be slightly weaker above a
hollowed-out region, so people look for places where gravity is weakest. But
this “gravimetry” method often fails—when the vast mass of a mountain,
say, overwhelms the weak change near a bunker. Now there’s a way around this,
says James Battis of the Air Force Research Lab (Journal of Physics D,
vol…
