[JoeFromSidney]

"Unobtanium" is a movie development standard placeholder (like "MacGuffin) in scripts or treatments, usually replaced by some name at the last minute.

Engineers have been using the term for years, as in, "That thing won't fly unless you make it of pure unobtanium."

[freedumb2003]

>>Engineers have been using the term for years, as in, “That thing won’t fly unless you make it of pure unobtanium.”<<

I didn’t know that. But it makes sense from an Engineering POV.

Physicists tell you what can’t be done. Engineers do it anyway.