Explosion of life on Earth linked to heavy metal act at planet’s centre

Formation of solid iron core 550m years ago restored magnetic field and protected surface

At the centre of the Earth, a giant sphere of solid iron is slowly swelling. This is the inner core and scientists have recently uncovered intriguing evidence that suggests its birth half a billion years ago may have played a key role in the evolution of life on Earth.

At that time, our planet's magnetic field was faltering - and that would have had critical consequences, they argue. Normally this field protects life on the surface by repelling cosmic radiation and charged particles emitted by our sun.