Earlier this year we looked at a "multiwalled carbon nanotube (MCNT) aerogel" -also dubbed "frozen smoke" - that, with a density of 4 mg/cm3, became the world's lightest solid material. Now frozen smoke has been knocked off its perch by a new metallic material with a density of just 0.9 mg/cm3, making it around 100 times lighter than Styrofoam. Despite being 99.99 percent open volume, the new material boasts impressive strength and energy absorption, making it potentially useful for a range of applications.
via gizmag.com
I love the picture, I saw it on the newspaper this morning and went looking for the article online just to post it here. :)