Scientists discover strong, unexpected link between Earth's magnetic field and oxygen levels

Trees shadowed against a pink and red sky created by the northern lights in Poland.

Earth's magnetic field and oxygen levels are inextricably linked, new research suggests.

The strength of the geomagnetic field has gone up in lockstep with the percentage of oxygen in Earth's atmosphere over the past 540 million years, a new study finds — but it remains unclear if one of these influences the other, or whether other unknown factors explain the link.