According to a new study, partial or temporary shifts in Earth's magnetic poles can occur much, much faster than was previously thought possible — potentially, within a single human lifetime. An international team of scientists analysed the geomagnetic history coded into the atoms of an ancient stalagmite in China. It showed them that once, about 98,000 years ago, the planet's magnetic field suddenly flipped polarity in as little as 100 years — roughly 30 times faster than the generally expected rate, and 10 times faster than what was thought to be the fastest rate possible.
Knowing that is important, mainly because our magnetic shield can diminish to about 10% effectiveness when it's in the middle of a reversal. Solar weather events, such as solar flares and solar wind storms, occur when blazing-hot, supercharged particles of energy blast out of the Sun's surface toward Earth. Even when our planet's magnetic field is at its strongest, a powerful enough solar storm can rip right past those defences and wreak havoc on anything electrical.
That surge of charged particles can garble radio signals, fry satellite and spacecraft instruments, and overload circuit breakers to take down entire power grids. That has already happened in Quebec, Canada, in 1989. An earlier, even larger solar storm in 1859, known as the Carrington event, caused telegraph wires to short-circuit all around the USA, throwing off sparks that started fires and electrocuted office workers.
Storms far less powerful than these could cause much more damage if they happened to hit while Earth's magnetic field was in the midst of a reversal. We know that it will happen again, and we now know it can occur very fast.
Featured image credit: NASA / Marshall Space Flight Center