A planetary magnetosphere is a region around a planet dominated by its magnetic field. This magnetic field is generated by the movement of molten metal in the planet's core, creating a protective shield against solar wind and cosmic radiation. The magnetosphere helps to maintain the planet's atmosphere and can influence weather patterns and space weather. Different planets have varying types of magnetospheres. For example, Earth has a strong magnetosphere that protects life from harmful radiation, while Mars has a weak magnetosphere, which contributes to its thin atmosphere. Understanding these magnetospheres is crucial for studying planetary environments and potential habitability.