Hot liquid that churns around Earth’s outer core powers a gigantic magnetic field that’s been hugging our planet since its infancy, protecting it from harmful solar radiation. But this magnetic field is known to get restless — and a couple of times every million years or so, the poles flip, and magnetic south becomes magnetic north and vice versa.
Now, a new study suggests that the magnetic poles can flip much more frequently than scientists thought. That’s what seems to have happened around 500 million years ago during the Cambrian period, when Earth’s creatures were undergoing evolutionary growth spurts, transforming into more complex life-forms.
To understand the workings of the magnetic field during this time, a group of researchers from the Institute of Physics of the Globe of Paris and the Russian Academy of Sciences collected sediment samples from an outcrop in northeastern Siberia.