The terrorist attack on the London subway system provoked calls from politicians for deploy-ment of new technologies that could warn of the presence of bombs before they go off. But a detector that can discov--er the presence of multiple types of explosives quickly, accurately and from a far enough distance to protect peo-ple and property does not exist. The nearest thing is a snif--fer dog, but a canine has a short attention span and needs frequent breaks.
The chemists, materials scientists and electronic engineers who are paid to think about such issues are trying to come up with ideas beyond putting Ritalin in dog chow. Large swaths of the electromagnetic spectrum and the periodic table are fair game. Even the insect kingdom might be recruited to attack the problem. A report by the National Research Council (NRC) last year--Existing and Potential Standoff Explosives Detection Techniques--speculated on far-out ideas for finding concealed bombs that use conventional explosives. Bees could be trained, through altered feeding habits, to swarm a vehicle packed with dynamite. Failing that, robotic "insects" with onboard sensors might do the same.