Earth's magnetosphere is an invisible shield, protecting our planet from harmful solar radiation. Many living organisms - from bacteria to insects or birds - seem to rely on Earth's magnetic field to navigate.
Man has been doing so for a thousand years since the invention of the compass. But research shows the magnetic field is weakening and scientists are trying to understand why. Some believe it signals a pole reversal in progress, not an uncommon phenomenon in the history of our planet.
As ground observatories fail to grasp the whole picture, we are sending magnetometers into orbit to try to measure the magnitude and the direction of the magnetic field. Find out more, this week, in Space.