A metallic lattice of hair-thin pipes is now the lightest solid yet created — less dense than air, scientists revealed. The strategy used to create these intricate structures could lead to revolutionary materials of extraordinary strength and lightness, including ones made of diamond, researchers added. Ultra-lightweight materials such as foams are widely used in thermal insulation and to dampen sounds, vibrations and shocks. They can also serve as scaffolds for battery electrodes and catalytic systems. The very lightest substances in the world until now, aerogels, have the ethereal nickname "frozen smoke.” They can reach densities of 1 milligram per cubic centimeter, making them less dense than air at room temperature and sea level. The problem until now with low-density materials such as aerogels and metallic foams has been their random structures. For instance, aerogels are derived from gels whose liquid components were replaced with gas, leaving behind solid tangles of microscopic-bead necklaces. The chaotic architecture of these substances makes them much weaker than conventional forms of their parent material. Now scientists have devised ultra-lightweight, low-density metallic lattices with orderly structures. These possess higher levels of stiffness, strength and conductivity of conventional forms of their parent materials, findings detailed in the Nov. 18 issue of the journal Science. Full article here.