Scientists have just unveiled the lightest human-made substance on Earth. How light are we talking? Let's put it this way: it's less dense than helium.
The battle for rights to the title of world's lightest material (technically world's lowest density material) has played out like a brutally rapid series of monarchal overthrows. For years, NASA's aerogel (density 1 milligram per cubic centimeter) held the title of lightest material on Earth. In November 2011, it was dethroned by a gorgeous, ultralight metallic microlattice (density 0.9 mg/cm3). Months later, a substance called "Aerographite" with a density of just 0.2 mg/cm3 blew both of these ultralight materials out of the water. Now, a new material has assumed the throne.