Ancient Trees Show When The Earth's Magnetic Field Last Flipped Out
A precise record of the last major reversal of the Earth's magnetic poles can be found in ancient trees. Researchers say this event 42,000 years ago had a huge impact on the planet and ancient humans.
An ancient, well-preserved tree that was alive the last time the Earth's magnetic poles flipped has helped scientists pin down more precise timing of that event, which occurred about 42,000 years ago.
This new information has led them to link the flipping of the poles to key moments in the prehistoric record, like the sudden appearance of cave art and the mysterious extinction of large mammals and the Neandertals. They argue that the weakening of the Earth's magnetic field would have briefly transformed the world, by altering its climate and allowing far more ultraviolet light to pour in.
Their provocative , in the journal , is sure to get that die-offs of large mammals seemed to occur in periods when the Earth's magnetic field was weak.
