The sound you can’t hear might just save your house. It sounds like something out of a sci-fi blockbuster, but firefighters in California are firing up a fascinating new way to fight flames — with sound waves. The San Bernardino County Fire Department recently showed off a futuristic system that detects and extinguishes flames without water or chemicals. Instead, it uses powerful — but completely silent — sound vibrations to snuff out the fire itself. The red-hot technology, inspired by NASA