June 2, 2004
The magnetosphere is an area of space, around a planet, that is controlled by that planet's magnetic field. Saturn is surrounded by a giant magnetic field, lined up with the rotation axis of the planet. This cannot be explained by current theories. Cassini may explain how the puzzling magnetic field of Saturn is generated.
This magnetic field may also cause strange features in the rings called 'spokes'. These markings fall across the rings like spokes in a wheel and may be caused by electrically charged particles caught up in the magnetic field, but there are as yet no detailed theories about them.
The brief reconnaissance encounters of the Pioneer 11 and the two Voyager spacecraft have provided most of our current information about the structure and dynamics of Saturn's magnetosphere.
Here are some things that we do know:
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