For a long time, aerogel was the lightest and least dense material ever made. Late last year, a metallic lattice structure took the crown. And today, the new champion is officially aerographite, with a density so low that it barely exists at all.
The density of aerographite is a mere 0.2 milligram per cubic centimeter. For the record, the next best thing (those metallic lattice structures) are three times heavier at about 0.9 milligram per cubic centimeter. This stuff is more or less entirely made out of air, with what little structure there is consisting of a network of hollow carbon tubes grown at nano and micro scales, which you can see in the electron microscope image above. A clump of it would look something like black sponge, appearing completely opaque despite its absurdly low density (unlike aerogel).
via DVICE
July 12, 2012