Scientists suspect magnetic fields in mass extinctions.

Science News looks at new research revisiting an old idea – that mass extinctions have something to do with reversals in Earth’s magnetic fields. The two phenomena are looking more and more like they line up in the fossil record:

During the past 2.5 million years, eight species of one-cell marine animals called Radiolaria became extinct. Six of these extinctions occurred simultaneously throughout their geographic range immediately following magnetic reversals.

Earth’s magnetic field protects the planet from cosmic and solar radiation, but that field can weaken during pole reversals.

SN also links to a 2016 study specifically of a mass extinction 550 million years ago to increases in solar radiation.