TIL Since the late 1950s, aerospace engineers have used the term "unobtainium" when referring to unusual or costly materials, or when theoretically considering a material perfect for their needs in all respects, except that it does not exist.

https://en.wikipedia.org/wiki/Unobtainium?wprov=sfla1
#til #todayilearned
https://www.reddit.com/r/todayilearned/comments/1g9p9i9/til_since_the_late_1950s_aerospace_engineers_have/