I keep reading this, but I'm missing what makes it special. If you create a large enough vessel of anything and evacuate all the air, you can make it lighter than air. Is it just that it's rare to find a material strong enough with respect to its density to withstand the necessary vacuum? (ie: would a titanium bubble with a sufficient volume to thickness ratio to be lighter than air implode? Or would it just be too expensive?)
Buckminster Fuller thought that if you built a large enough geodesic dome out of normal midcentury materials, you could get enough lift from sunlight-driven thermal expansion of air to float it. http://www.thirteen.org/bucky/cities.html
Pretty much, though it's unclear to me whether this material is even strong enough for that. But make it big and strong enough, and you can make even a lead balloon float.
