The writers for Avatar were extremely lazy. However Unobtanium has been an engineering in-joke since the '50s: http://en.wikipedia.org/wiki/Unobtainium http:/

The writers for Avatar were extremely lazy. However Unobtanium has been an engineering in-joke since the '50s: http://en.wikipedia.org/wiki/Unobtainium http://en.wikipedia.org/wiki/Unobtainium