Geomagnetism is the study of the Earth's magnetic field, which is generated by the movement of molten iron in the outer core. This magnetic field extends into space and protects the planet from solar winds and cosmic radiation. It also plays a crucial role in navigation, as compasses align with the magnetic field, helping travelers find their way. The Earth's magnetic field is not constant; it can change over time due to various factors, including solar activity and geological processes. These changes can lead to phenomena such as magnetic pole reversals, where the magnetic north and south poles switch places, occurring over thousands of years.