Space is a challenging place. We think of it as mostly empty,
but that is not completely true. The vast sea of space in our
solar system is filled with powerful radiation and bombarded
with high-speed atomic particles. In addition, the Sun generates
a continuous stream of particles that we call the "solar wind."
The high energy radiation, the high energy particles, and the
solar wind could prove dangerous to life here on Earth's
surface. Earth's planetary shield -- the Earth's magnetic field
working together with our atmosphere -- protects us. Every
magnet generates a magnetic field. Several objects in our solar
system also have their own massive magnetic fields: the Sun,
Earth, Mercury, Jupiter, Saturn, Uranus, and Neptune. The
magnetic field around a planet that extends into space is called
a magnetosphere. The magnetospheres of the planets interact with
the particles from the Sun -- the solar wind. Within the
magnetosphere, charged particles spiraling along the Earth's
magnetic field toward the poles creat