How stable is the Earth's magnetic shield?

The magnetic field surrounds the Earth like a protective shield. About 780,000 years ago, it reversed completely. About 41,000 years ago, there was a short-term reversal of polarity. Both events were accompanied by very low field strengths of the Earth's magnetic field, i.e., the protective shield effect of the magnetic field against solar wind and cosmic radiation was strongly reduced. It is not yet clear whether there was a planetary ecological crisis as a result and, if so, how dramatic it was. The magnetic field will reverse again, but we cannot say when that will be.

In addition to these millennia-long processes, there are also short-term degradations of the magnetic shield caused by powerful solar storms that threaten satellites and infrastructure. At the same time, they offer fascinating insights into radiation belts around our planet. We study both this short-term space weather and the long-term variations of the Earth's magnetic field to better understand how stable this protective shield, so important for our habitat, is.

Image: Sanja Panovska, Ahmed Nasser Mahgoub Ahmed, Maximilian Schanner / Deutsches GeoForschungsZentrum GFZ