Aerogel and the World's Lightest Solid

I'm sure this makes me unbelievably sad by just being interested but I think it's cool anyway. There's an amazing material that Nasa has developed with a one of Lyon's universities (and many other people I'm sure) which they are using as an insulator whilst collecting particles from the comet which they're trying to intercept at the moment. The 'aerogel' is a solid material which has amazing insulating properties because of its low density. It's made by making a solution of a silicate with methanol and then drying this under 'supercritical alcohol conditions'. Imagine using it to insulate a house.

Aerogel is pure silicon dioxide and sand, just as is glass, but aerogel is a thousand times less dense than glass because it is 99.8 percent air. It is prepared like gelatin by mixing a liquid silicon compound and a fast-evaporating liquid solvent, forming a gel that is then dried in an instrument similar to a pressure cooker. The mixture thickens, and then careful heating and depressurizing produce a glassy sponge of silicon.

What remains is sometimes called "solid smoke," for its cloudy translucent color and super-light weight. Surprisingly, this seemingly brittle substance is durable and easily survives launch and space environments.

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Nasa's Image Gallery of Aerogel