Aerogel is one of the most amazing materials in the world. I would encourage you to check out a picture of it. Aerogel is not like conventional foams, but is a special porous material with extreme microporosity on a micron scale. It is composed of individual features only a few nanometers in size. These are linked in a highly porous dendritic-like structure. Aerogel has some absolutely amazing properties:
- It is 99.8 percent air, lowest density of any solid
- Provides 39 times more insulating than the best fiberglass insulation
- Is 1,000 times less dense than glass
- Was used on the Mars Pathfinder Spirit
It also has the highest thermoinsulation properties. Though it would be very expensive, you could take a two- or three-bedroom house, insulate it with aerogel, and you could heat the house with a candle. But eventually the house would become too hot. NASA used this amazing material to capture portions of the Comet Wild 2 that passed near Earth recently.
NASA
New York Times January 20, 2004