Using Advanced Physics to Find Concealed Weapons

NY Times:"Three companies are racing to market a new form of technology for detecting concealed weapons, using physics borrowed from radio astronomy and manufacturing techniques from cellular phone makers. The technology, called millimeter wave, is a new category of sensing so unobtrusive that it seems like something out of 'Star Trek.' Unlike conventional systems such as metal detectors, which sense magnetic fields created by certain materials or objects, or X-ray machines, which pass rays through objects, millimeter wave sensors are passive and rely on detecting energy emitted by objects."