A magnetosphere is a region around a celestial body, like a planet, where its magnetic field interacts with charged particles from the solar wind. This magnetic field helps protect the planet from harmful solar radiation and cosmic rays, creating a shield that can prevent atmospheric erosion. Earth's magnetosphere extends thousands of kilometers into space and is shaped by the solar wind's pressure. Other planets, such as Jupiter and Saturn, also have magnetospheres, but they vary in size and strength. Understanding magnetospheres is crucial for studying space weather and its effects on satellites and communication systems.