Harry Potter got a lot of mileage out of invisibility in the “Harry Potter” series. Not being seen is a key tactic in every warfighter’s toolkit. Earlier warriors adopted camouflage to blend into their surroundings. Modern-day hardware relies on stealth technology, design and materials to make aircraft, naval vessels and vehicles harder to pick out by radar, sonar or heat-sensitive sensors. Invisibility, though, is the Holy Grail in stealth. And the British Army claims to have found it, albeit in a rather kludgy way. In secret tests in 2007, they coated a tank in silicon, turning it into something like a movie screen. Video cameras on the tank take footage of the tank’s environment in real time and project the images on the surface of the tank. Voila, an invisibility cloak of sorts. Not to be outdone, the boffins at the U.S. Defense Advanced Research Projects Agency (DARPA) have launched their own work to investigate “urban obfuscants” to develop protective shields for soldiers in urban combat situations.

Seven Sci-Fi Weapons from Tomorrow Are Here Today