While the earth’s geomagnetic field has been decreasing over the past two centuries, and the average duration between flips tends to be about a few hundred thousand years, the fact being that earth hasn’t experienced a reversal in 780,000 years, is leading scientists to believe it’s time.

But a recent study shows that the intensity of today’s field is still uncharacteristically strong. When the geomagnetic field intensity is significantly below its historical, long-term average, a geomagnetic swap may be on its way. We are far from that happening, about 1,000 years at least. Not to mention, it has been impossible to narrow down on any kind of pattern regarding the switch frequency as the decreasing geomagnetic field might have a change in heart and start building itself up again anytime.

“It makes a huge difference, knowing if today’s field is a long-term average or is way above the long-term average,” noted lead author Huapei Wang in MIT News. “Now we know we are way above the unstable zone. Even if the [field intensity] is dropping, we still have a long buffer that we can comfortably rely on.”

Now, why is it important to predict this inevitable switch of polarity? The Earth’s magnetic field actively deflects solar wind and cosmic rays and a weakened field would allow the entry of solar radiation that could have serious repercussions on biological life such as genetic mutations. It could even result in mass extinctions; scientists speculate that previous polar flips have done exactly this. In short, the longer the field is decreasing, more harmful rays are getting through to us.

There are also errors that could affect the technological infrastructure (satellites, power grids, sensitive equipment like pacemakers and the sort).Now, more about this new study- Scientists from MIT and Columbia University’s Lamont-Doherty Earth Observatory arrived at their conclusion by analyzing ancient rocks erupted from volcanoes on the Galapagos Islands, chosen for its location on the equator, where the strength of the Earth’s magnetic field is exactly half of what it is at the poles. Cooling lava makes the iron-bearing minerals within in it act like tiny magnets that align perfectly with the earth’s magnetic field giving a sense of its direction and intensity. The results suggest that the time-averaged geomagnetic field intensity over the past 5 million years is about 60% of the field’s intensity today.

“What I can say is, if you keep a constant present-day decrease rate, it will take another 1,000 years for the field to drop to its long-term average,” Wang told MIT News. “From there, the field intensity may go up again. There’s really no way to predict what will happen after that, given the random nature of the [geomagnetic process].”

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Author:Technology Blog