There are several good articles about the magnetosphere online.
http://science.nasa.gov/ssl/pad/sppb/Edu/magnetosphere/
http://en.wikipedia.org/wiki/Magnetosphere
In a nutshell, the magnetosphere is due to the iron core and strong magnetic field of earth, and it protects earth from bombardment of cosmic charged particles and solar winds.
Magnetosphere
If we did not have the Magnetosphere we would die from harmful Solar Wind that the Magnetosphere blocks. The Magnetosphere is like our personal shield along with our atmosphere!
The Earth's magnetosphere acts as a shield, protecting the planet from the solar wind and cosmic radiation by deflecting charged particles. It also helps prevent the atmosphere from being stripped away into space. The magnetosphere interacts with the solar wind, forming a protective barrier around the Earth.
the sun and the Earth's magnetic field create the magnetosphere.
Magnetosphere of Jupiter was created in 1973-12.
The sun's rays create a protective barrier around Earth called the magnetosphere. This magnetosphere deflects and traps cosmic radiation, preventing it from reaching the surface of the planet and harming living organisms.
Amalthea Magnetosphere was created on 2006-05-17.
The Earth's magnetosphere has flipped. It is the opposite as it was thousands of years of go.
The magnetosphere primarily attracts and deflects charged particles from the solar wind, such as protons and electrons. These particles are trapped and guided along the magnetic field lines of the Earth's magnetosphere, creating phenomena like auroras.
The Magnetosphere is that area of space, around a planet, that is controlled by the planet's magnetic field. The shape of the Earth's magnetosphere is the direct result of being blasted by solar wind. It does not attract the solar wind but it defends life on our planet by preventing most of the particles from the Sun, carried in the solar wind, from hitting the Earth.
The magnetosphere is important because it acts as a protective shield around Earth, deflecting harmful solar wind and cosmic rays. Without the magnetosphere, these particles could strip away the atmosphere and make it difficult for life to exist on Earth. Additionally, the magnetosphere plays a key role in generating phenomena such as the auroras.
Jupiter's magnetosphere has a complex magnetic field with multiple poles. Unlike the Earth, which has a relatively simple dipole magnetic field, Jupiter's magnetic field is generated by a combination of its internal dynamo and interactions with its moons.