I'm curious whether or not it is possible to make a vacuum by taking a rigid, hollow sphere and forming a vacuum inside of it. Presumably this is possible if you just assume the material it is made out of is infinitely strong and rigid (it just needs to weigh less than the equivalent volume of air). However, I'm curious if this is possible with any materials we know about.

It was made around 25¿? years ago.

I remember reading but not much more details than being about 50cm diameter and made of glass, as thin as a soap bubble.

My considerations about such a balloon are there:

http://saposjoint.net/Forum/viewtopic.php?f=66&t=2520

 

The easiest I could imagine was a skin on a truss. Not extremely complicated then, but a very nice challenge.

Thanks enthalpy, that's just what I was looking for.