At several times in Earth’s history, mass extinctions have come close to wiping life out altogether. The reasons for these catastrophes are still unclear – they’ve been blamed on everything from asteroid impacts to cosmic ray blasts. But a new study has found that our planet itself could have a surprising hand in these disasters.
Research recently published in Earth and Planetary Science Letters suggests that reversals of the Earth’s magnetic field may have sparked mass extinctions in the past by stripping oxygen from the atmosphere.
main geomagnetic field
The Earth’s natural magnetic field, generated in the liquid outer core, spontaneously changes direction every 500,000 years or so. Known as geomagnetic reversals, these processes cause the field’s north and south poles to swap places.
Normally, the Earth’s magnetic field acts like a shield around the atmosphere, protecting it from the damaging effects of the solar wind (the supersonic stream of ...
