This is a picture of the lightest substance on Earth - io9

via brain teasers - Google News http://news.google.com/news/url?sa=t&fd=R&usg=AFQjCNFEXaJSDQrvyPXygdY6k_oB_E789A&url=http://io9.com/this-is-a-picture-of-the-lightest-substance-on-earth-461681135