Earth’s magnetic field almost disappeared 565 million years ago

If you thought you were having a bad day, think again – the Earth almost lost its magnetic field 565 million years ago. But it may have been saved by a geo-dynamic phenomenon according to a new study.

The study, published in Nature Geoscience, shows that Earth’s core, which was still young and liquid at the time, started to harden, in turn strengthening the magnetic field and preventing the Earth from being zapped by solar winds and the radiation that is abundantly prevalent in space.

“Together with 14 other directional data sets that suggest a hyper-reversal frequency, these extraordinary low field strengths suggest an anomalous field behavior, consistent with predictions of geodynamo simulations, high thermal conductivities and an Ediacaran onset age of inner core growth,” researchers wrote in the study.

The researchers looked at samples of plagioclase and clinopyroxene from eastern Quebec, Canada and found that they contain magnetic needles approximately 50 to 100 nanometers in size, surprising the researchers.

“Those tiny magnetic particles are ideal magnetic recorders,” study co-author John Tarduno told LiveScience. “When they cool, they lock in a record of Earth’s magnetic field that’s maintained for billions of years.”

They were able to determine that the particles inside the crystals had a very low charge, Tarduno added, noting that the Earth was at a “critical point where the dynamo almost collapsed completely.”

Once the geodynamo, which causes the growth and maintenance of the magnetic field, got a proverbial jump start from the hardening of the Earth’s core, the charged particles kept moving and the magnetic field strengthened.

Follow Chris Ciaccia on Twitter @Chris_Ciaccia

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