A new MIT study suggests that there is little danger of Earth's geomagnetic field flipping in the near future. Previous research in the area had predicted an imminent flip (in geological terms) that would leave all life on Earth temporarily un-shielded from a plethora of dangers posed by deep space phenomenon.
Generated from deep within our planet, Earth's geomagnetic field acts as a protective shield, guarding us from dangerous space weather and charged particles that would otherwise pose a dire threat to life on Earth. An analysis of rock samples has informed us that – seemingly unpredictably throughout Earth's history – the geomagnetic field flips, leaving it temporarily unprotected.
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During this transitional period, which could endure for several thousand years before the field reasserts itself enough to regain its protective qualities, we as a species would be exposed to a vast increase in solar radiation that could potentially cripple our technology and create severe genetic mutations.
The last recorded flip took place roughly 780,000 years ago, and based on data collected from the ground and in orbit has suggested that Earth's geomagnetic field has been in steady decline for roughly 200 years, leading some to predict that the field may flip again in around 2,000 years.
The new MIT-led research may lead to a dramatic rethink of this model. The team behind the research was able to accurately deduce the average field intensity for the past five million years based on an analysis of volcanic rock samples collected from the Galapagos Islands located near Earth's equator, and further samples extracted from Antarctica.
It was discovered that the strength of Earth's geomagnetic field during shielding periods had an average intensity of 15 microtesla at the equator, and 30 microtesla at the poles. The present day strength of the geomagnetic field has been measured at 30 microtesla at the equator and 60 microtesla at the poles, placing it significantly above the historical average.
Scientists behind the research believe that previous studies in this area had suffered from a fatal flaw, which led to the more ominous predictions of an imminent field flip. Prior work had misinterpreted how volcanic rocks recorded the presence of magnetic fields. For the new study, scientists corrected the error, and for the first time collected equatorial samples, allowing for a more accurate estimation of the average ancient field strength.
This means that even though Earth's geomagnetic field is steadily losing intensity, it will still take around 1,000 years to dip to the newly-defined historic average. From this point, it is possible that the field may then stabilize and maybe even increase in strength. Further studies are required to better understand the complicated characteristics of our planet's geomagnetic field, and the potential threat that a reversal could pose.
A paper on the discovery is available online in the Proceedings of the National Academy of Sciences.