Aerogel is a “silicon-based solid with a porous, sponge-like structure in which 99.8 percent of the volume is empty space,” resulting in the lightest solid material known to man. It was initially created as a means to trap cometary particles and interplanetary dust aboard the Stardust Spacecraft, since it can slow down and trap such particles without damaging them. I know this is older news, but I came upon this photo gallery and FAQ and was very intrigued.
