
© WikipediaComputer simulation of the Earth's field in a period of normal polarity between reversals.[1] The lines represent magnetic field lines, blue when the field points towards the center and yellow when away. The rotation axis of the Earth is centered and vertical. The dense clusters of lines are within the Earth's core.[2]
New paper confirms what I said in both
Not by Fire but by Ice and
Magnetic Reversals and Evolutionary Leaps, that low magnetic-field strength during magnetic reversals can trigger both extinctions and evolution.
Unfortunately, magnetic-field strength is now declining rapidly.**
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New fossil finds, improved fossil dating, knowledge of the past strength of Earth's magnetic field, and refinements in the human evolutionary tree, suggest a link between ultraviolet radiation (UVR), magnetic field strength, and mammalian evolution, says a new paper by Channell and Vigliotti.
The earth's magnetic field shields us from galactic cosmic rays and solar wind, and from harmful UVR. During magnetic reversals, that protection declines.Over approximately the last 200,000 years, evolutionary changes corresponding to low geomagnetic-field strength support the proposition that UVR that can affect mammalian evolution by influencing DNA and Y chromosomes.
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