Along with personal jetpacks for every man, woman, and child (sure, why not), levitation is one of those conveniences that sci-fi has long promised us but has yet to deliver, other than magnetically ...

In fiction, magic makes levitation easy. With a simple swish-and-flick of his wand, Ron Weasley yanks a troll’s club high above its head in Harry Potter and the Sorcerer’s Stone. Through graceful ...