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Images courtesy of Wikipedia [magnetic field diagram] and NASA, ESA, L. Sromovsky and P. Fry (University of Wisconsin), H. Hammel (Space Science Institute), and K. Rages (SETI Institute) [Uranus photo].
The Magnetic Poles of Uranus
Uranus has a strange magnetic field. The magnetic poles of Uranus are not at all close to the geographic poles of Uranus.
The main magnetic field of Uranus is tilted 59° away from the planet's spin axis. Earth's magnetic field is tilted, too... but only by 11°. The magnetic field of Uranus is shifted, too. It doesn't quite go through the center of the planet.
The magnetic field of Earth is pretty much like the magnetic field around a bar magnet. It has a North Pole and a South Pole. It is called a dipole ("two poles") field. The magnetic field of Uranus is more complicated. It has a dipole part... but it also has a part with four poles. With all of these poles and its crazy tilt, the magnetic field on Uranus varies a lot from place to place. In some places in the southern hemisphere of Uranus the magnetic field is only 1/3rd as strong as Earth's field. However, in some parts of the North the field on Uranus is almost four times as strong as Earth's!
Why is the Uranian magnetic field so odd? Scientists think that electrical currents in a salty ocean inside Uranus may create its magnetic field. That ocean isn't at the core of Uranus. Most planets make their magnetic field at their core. Maybe that's why the field around Uranus is so odd. Neptune is the other planet most like Uranus. Neptune has a strange magnetic field, too.
The spin axis of Uranus is tilted 98° and the magnetic field is tilted 59°. Scientists thought that these tilts would give Uranus a very strange magnetosphere. Guess what? The magnetosphere of Uranus is pretty much normal, like other planets. Scientists are still trying to figure out why. They do know that Uranus has aurora... like the Southern and Northern Lights on Earth.
