Final answer:
Earth's magnetic field is thought to originate from the movement of conducting materials in the outer core, which creates electric currents and a corresponding magnetic field. This field forms the Earth's magnetosphere, which protects us from solar and cosmic radiation and influences navigation.
Step-by-step explanation:
Scientists believe that Earth's magnetic field is produced by the movement of liquid metallic materials in the outer core. This movement generates electric currents, leading to a circulating magnetic field similar to that of a giant bar magnet. The core's motion is driven by heat creating convection currents within the fluid metal. These currents of charged particles generate the magnetic field that surrounds our planet.
The Earth's magnetic field is crucial for life on Earth as it protects us from harmful solar wind and cosmic radiation. This protective shield is known as the magnetosphere, and within it, we find phenomena such as the Van Allen radiation belts. The magnetic field also influences navigational tools like compasses which align with the field to indicate magnetic north, although it should be noted that magnetic north differs slightly from true north.