Dr.T, sorry about that. I hit the wrong button by mistake. Now getting back to it. JKR wrote a FANTASY series. Not a reality series. Thus her numbers don't have to work in reality. If she wrote that the sky is always green above Hogwarts then it's always green. If it WAS real then we'd have all sorts of interesting gismos from scifi and fantasy. Such as colonies on other world, FTL travel and communications, teleportation, psi powers MAGIC, aliens living among us, both scifi and fantasy types. So don't sweat the small stuff. Damn good story this!