Science | February 20, 2021 1:22 pm

42,000 Years Ago, Earth’s Magnetic Field Collapsed. Now Scientists May Know What Came Next.

All this and a Douglas Adams homage, too.

Cave painting
Did an environmental catastrophe lead to a boom in cave painting?
Sautuola1880 - CC BY-SA 4.0

It’s not hard to see why the mysteries of human life in prehistoric times is such a compelling subject for so many people. While the last few thousands of years of human history abound with records of societies from around the globe, the full breadth of humans’ time on the planet extends back for far longer. And now, a provocative new study offers details on how a bizarre set of environmental conditions might have shaped human evolution.

A new report in The New York Times by Alanna Mitchell ventures into the provocative findings of a group of Australian scientists. The scientists drew upon research on a kauri tree that stood for thousands of years before falling in a swamp and being preserved until the present day. What makes this tree especially intriguing was the time it lived: 42,000 years ago, when the planet’s magnetic field collapsed.

In a paper published in Science, a group of 33 scientists used radiocarbon data to gain a more precise understanding of the time in which the tree lived. Mitchell writes that this occurred “when the magnetic poles attempted unsuccessfully to switch places” — formally known as the Laschamp excursion. As a result, the planet’s magnetic field dissipated.

Scientists were already aware that the Laschamp excursion coincided with other significant events, including the death of Neanderthals, extinction of large animals in Australia and the rise of cave painting. The new paper suggests that the loss of the planet’s magnetic fields may have been at the root of all of these events.

The researchers dubbed the years that led to the Laschamp excursion as the Adams Transitional Geomagnetic Event. That’s a tribute to the late writer Douglas Adams, who wrote movingly about the extinction of species on the planet and also had a fondness for the number 42. It makes for a fascinating juxtaposition of past and future.

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