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.

Lithium (from Greek lithos or stone) is a silvery-white alkali metal that is the lightest solid element. Just one atomic step up from Helium, this magic metal seems to be in everything these days.

This remarkable gel is the world's lightest solid. Since its invention in 1931 by American scientist Samuel Kistler, it has been used in space missions to collect dust from a comet's tail ...