Which phenomenon is believed to cause Earth's magnetic field?

The phenomenon that is believed to cause Earth's magnetic field is the geodynamo effect. This process involves the movement of molten iron and other conductive materials in Earth's outer core. As these fluids move due to convection currents driven by heat from the inner core and the rotation of the Earth, they generate electric currents. According to electromagnetic theory, these electric currents produce magnetic fields. The combination of these magnetic fields creates a more extensive and stable magnetic field around the Earth.

This geodynamo effect is fundamental to our understanding of Earth's magnetism and can explain the alignment of the magnetic poles, the generation of magnetic field lines, and the overall structure of the magnetic field. The Earth's magnetic field plays a crucial role in protecting the planet from harmful solar radiation and helps maintain a stable environment for life.