The Swarm satellites were used to create this image — the most detailed map of the Earth’s magnetic field ever made! The areas where the magnetic field is weaker are shown in blue, and the strongest regions are red. These differences are caused by the shape of Earth’s crust.
Shown here is an area of the Central African Republic where the magnetic field is particularly strong and concentrated. The cause for this anomaly is still unknown, but some scientists think it’s the result of a meteorite impact more than 540 million years ago!