Earth's magnetic field has reversed multiple times in the past (the graphic on Wikipedia shows ~20 in the past 5 million years). I don't think we knew why, but

Earth's magnetic field has reversed multiple times in the past (the graphic on Wikipedia shows ~20 in the past 5 million years). I don't think we knew why, but this could be it. Given the frequency of it, this isn't likely to be catastrophic from a biological perspective, but might cause havoc technologically. https://en.wikipedia.org/wiki/Geomagnetic_reversal https://en.wikipedia.org/wiki/Geomagnetic_reversal