What if you could wear lightweight armor that kept you warm – and let you phone home? Nanotechnologists have come up with a super strong, flexible fiber that can conduct heat and electricity. It could be made into a modern version of chain mail, the heavy metal mesh worn by medieval knights. If woven from the new fiber, modern chain mail could be light as a cotton shirt, but bulletproof. Molecular Chain Mail Over hundreds of millions of years of evolution, many animals, plants, and natural materials have developed extraordinary properties. Spider silk, for example, is five times tougher than...