Earth's magnetic field
Characteristics
A nanotesla is also referred to as a gamma (γ). The tesla is the SI unit of the magnetic field, The Earth's field ranges between approximately 25,000 and 65,000 nT (0.25–0.65 G). By comparison, a strong refrigerator magnet has a field of about 10,000,000 nanoteslas (100 G). A map of intensity contours is called an isodynamic chart. As the World Magnetic Model shows, the intensity tends to decrease from the poles to the equator. A minimum intensity occurs in the South Atlantic Anomaly over South America while there are maxima over northern Canada, Siberia, and the coast of Antarctica south of Australia.
Earth's magnetic field-9