For decades, we've thought we had a pretty good grasp of Uranus.

The penultimate planet, our best measurements suggest, has a whole slew of idiosyncrasies. And one of the most puzzling is its magnetic field. According to measurements taken by Voyager 2 when the NASA probe conducted a flyby in 1986, Uranus's magnetosphere is a hot mess – off-center and off-kilter, unlike anything else in the Solar System.