Imagine the Earth flipping over completely, up being down, north being south … sounds crazy, right? But new evidence suggests that around 16 million years ago, magnetic north and south interchanged in the span of just a few years!
Theoretically, flips which are so fast are impossible in terms of the Earth core models, but such evidence has been unearthed for the second time lending more credence to the theory.
In the normal course of events, the magnetic south and north poles interchange in cycles of around 300,000 years, and each so-called flip takes up to 5,000 years to complete. This theory was first put to the test in 1995, when ancient lava flows in Oregon were discovered to have strange and unusual magnetic patterns. These indicated that the magnetic field was shifting at a rate of close to six degrees a day – about 10,000 times faster than the normal rate. However, this evidence didn’t convince most scientists, so Scott Bogue from Occidental College, Los Angeles, felt further proof was needed.
Bogue and his co-researcher, Jonathan Glen from the US Geological Survey, based in Menlo Park, California, are claiming to have found other evidence for the flip, this time in Nevada. Their research findings, published in Geophysical Research Letters, indicate lava flows in the area suggest the Earth’s magnetic field shifted by approximately 53 degrees in just one year. If that was the rate at the time, a complete “full flip” would have taken less than four years, and the Earth would have turned upside down.
Many are sceptical of this development. Peter Olson, from Johns Hopkins University in Baltimore, Maryland, feels this event was highly unlikely, and that the changes observed might just have been local and not global. Bogue himself admits that the data could be interpreted by assuming a small burst of fast acceleration which interspersed the steady movement of the magnetic field.
Rapid shifts or full flips could be chaotic for Earth right now, and navigation would be thrown completely off track. This would affect migratory birds and other animals that traverse long distances across the globe. Earth is expected to undergo a reversal soon, but let us hope that it is of the slow and steady kind after all. DM
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