World’s lightest (least dense) Solid
Aerogels are the world’s lightest (least dense) solids. They are also excellent thermal insulators and have been used in numerous Mars missions and the Stardust comet particle-return mission. The focus of this video is silica aerogels, though graphene aerogels are now technically the lightest.
At one point Dr. Steven Jones literally held the Guinness World Record for making the lightest aerogel and therefore lightest solid. If you’re interested in learning more about aerogels, let me know in the comments as there is a potential trilogy in the works
Credit to : Veritasium