A magnetosphere is created through the interaction between a planet’s magnetic field and a stream of charged particles. For example, when the solar wind interacts with Earth’s intrinsic magnetic field, the stream of charged particles from the solar wind will be deflected by the planets own magnetic field. This results to what scientists call a magnetosphere which surrounds the Earth and other planets that have intrinsic magnetic fields. The planets Jupiter, Mercury, Neptune, Saturn and Uranus have intrinsic magnetic fields and are also surrounded by a magnetosphere. Venus and Mars on the other hand have weak magnetic fields. They do not have magnetosphere because the solar wind flow is only partially deflected. This interaction occurs in the ionosphere of the planets with weak magnetic fields.

Before the magnetosphere was discovered by Explorer 1 in 1958, many scientists have already observed magnetic storm disturbances due to solar eruptions. Because of this, they have assumed that there should be some kind of electric currents that exist in space. However, the location of the said electric currents was not fully determined nor the existence of the solar wind until tests about a theory of radiation belt around the Earth was launched in 1958. The following year, Thomas Gold already proposed the term magnetosphere to identify the region above the earth’s ionosphere.