Image: “Supercomputer models of Earth’s magnetic field: On the left is a normal dipolar magnetic field, typical of the long years between polarity reversals. On the right is the sort of complicated magnetic field Erath has during the upheaval of a reversal,” written by Aaron Gronstal, 23 November 2017, in “Research Highlight: Reversing the Geomagnetic Field,” in Astrobiology at NASA: Life in the Universe … https://astrobiology.nasa.gov/news/reversing-the-geomagnetic-field/ … public domain

Image: “Supercomputer models of Earth’s magnetic field: On the left is a normal dipolar magnetic field, typical of the long years between polarity reversals. On the right is the sort of complicated magnetic field Erath has during the upheaval of a reversal,” written by Aaron Gronstal, 23 November 2017, in “Research Highlight: Reversing the Geomagnetic Field,” in Astrobiology at NASA: Life in the Universe … https://astrobiology.nasa.gov/news/reversing-the-geomagnetic-field/ … public domain

Dear Ones,

The Laschamp Excursion was a flip of Earth’s magnetic poles for several hundred years that took place 41,000 years ago, per tree ring analysis in New Zealand. Right before the Excursion Earth’s magnetic field weakened, resulting in more cosmic rays hitting Earth …

This must have been a little like what happened on Earth during the recent Solar Minimum that has just ended in the last year or so; during the recent Minimum cosmic rays also flooded into Earth.

Cosmic rays can result in genetic mutations in Earth animals and plants that speed the evolution of some animals and plants … that give them a competitive edge as an Earth species. Or, the genetic mutations can be harmful to the competitive edge of the species, and lead to its extinction.

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