Earth’s magnetic field, which is vital to protecting life on our planet from solar radiation, is mysteriously weakening. On average the planet’s magnetic field has lost almost 10% of its strength over the last two centuries, but there is a large localised region of weakness stretching from Africa to South America. Known as the South Atlantic Anomaly, the field strength in this area has rapidly shrunk over the past 50 years just as the area itself has grown and moved westward. Over the past five years a second centre of minimum intensity has developed southwest of Africa, which researchers believe indicates the anomaly could split into two separate cells. The anomaly is causing technical difficulties for satellites orbiting the Earth.