Invented: World's Lightest Material, 99.99 Percent Air

Micro-Lattice on Dandelion Dan Little © HRL Laboratories, LLC

A collaboration of researchers from HRL, CalTech, and UC Irvine have created the new world's lightest material--some 100 times lighter than styrofoam. It's even lighter than aerogel, one of our favorite ultralight materials.

The material is a micro-lattice in structure, with the 0.01 percent of the material that's solid consisting of hollow tubes that are only 100 nanometers thick. It's rated at a density of 0.9 mg/cc, lighter than even the lightest aerogels, which have only achieved 1.1 mg/cc. It's also extraordinarily strong and shock-absorbent, thanks to all that air: it can compress by 50 percent and completely recover its shape, highly unusual for a material that is essentially metallic. It was actually inspired by architectural structures rather than other ultralight materials--the team looked to the Golden Gate Bridge and the Eiffel Tower to see how those structures are so light and yet so strong.
The project was undertaken for, who else, DARPA, which says it could be used for products ranging from battery electrodes to energy damping in addition to insulation, the main use for prior lightweight champ aerogel.