o be nonexistent. The magnetic fields of Earth and other planets are believed to arise from electrical currents produced in their molten cores, but if Uranus possessed one, it would be too small and too deep for it to create such a magnetic field. As with Mercury, Earth, Jupiter and Saturn, there is a magnetic tail extending millions of miles behind Uranus. Voyager measured the tail to be at least 10 million kilometers (6.2 million miles) behind the planet. The extreme tilt of the magnetic axis, combined with the tilt of the rotational axis, causes the field lines in this cylindrical magnetic tail to be wound into a corkscrew shape that spins like a lawn sprinkler across the galaxy.The exotic magnetosphere of Uranus is contrasted by the planet's rather mundane ring system. Like the other gas planets, Uranus has rings. They are very dark in color like Jupiter's, but more like Saturn's rings in size and composition with both fine dust and large particles ranging up to 10 meters in diameter. There are 11 known rings, all relatively faint, the brightest of which is known as the Epsilon ring. The Uranian rings were the first after Saturn's to be discovered - which was of considerable importance since we now know that rings are a more common feature of planets than first thought, and not a peculiarity of Saturn alone. All nine of the previously known rings of Uranus were photographed and measured by Voyager 2, as were other new rings and ringlets in the Uranian system. These observations showed that while Uranus's rings shared similarities with the systems of Jupiter and Saturn, they are also distinctly different. Radio measurements from Voyager 2 showed the outermost ring, the epsilon, to be composed mostly of ice boulders several feet across. However, a very tenuous distribution of fine dust also seems to be spread throughout the ring system. Incomplete rings and the varying opacity in several of the main rings leads scientists ...
