Finally, you can buy the world’s lightest known solid. What are we talking about? Aerogel, it’s chemically similar to glass, yet ultra strong structurally, and has a melting point of 2,200 degrees F (1,200 degrees C). With a density of just 3 milligrams per cubic centimeter, it weighs only three times that of air. It’s been used in the Mars Pathfinder Rover to shield components from the extreme temperatures found on Mars. Get your own sample of Aerogel today, a small sample will run you $30 and $125 for a large. Source: [OhGizmo]