A new MIT studysuggests that there is little danger of Earth's geomagnetic fieldflipping in the near future. Previous research in the area hadpredicted an imminent flip (in geological terms) that would leave alllife on Earth temporarily un-shielded from a plethora of dangers posedby deep space phenomenon.
Generated from deepwithin our planet, Earth's geomagnetic field acts as a protectiveshield, guarding us from dangerous space weather and chargedparticles that would otherwise pose a dire threat to life on Earth.An analysis of rock samples has informed us that – seeminglyunpredictably throughout Earth's history – the geomagnetic fieldflips, leaving it temporarily unprotected.
During thistransitional period, which could endure for several thousand yearsbefore the field reasserts itself enough to regain its protectivequalities, we as a species would be exposed to a vast increase insolar radiation that could potentially cripple our technology andcreate severe genetic mutations.
The last recorded fliptook place roughly 780,000 years ago, and based on data collectedfrom the ground and in orbit has suggested that Earth's geomagneticfield has been in steady decline for roughly 200 years, leading someto predict that the field may flip again in around 2,000 years.
The new MIT-ledresearch may lead to a dramatic rethink of this model. The teambehind the research was able to accurately deduce the average fieldintensity for the past five million years based on an analysis ofvolcanic rock samples collected from the Galapagos Islands locatednear Earth's equator, and further samples extracted from Antarctica.
It was discovered thatthe strength of Earth's geomagnetic field during shielding periodshad an average intensity of 15 microtesla at the equator, and 30microtesla at the poles. The present day strength of the geomagneticfield has been measured at 30 microtesla at the equator and 60microtesla at the poles, placing it significantly above thehistorical average.
Scientists behind theresearch believe that previous studies in this area had suffered froma fatal flaw, which led to the more ominous predictions of animminent field flip. Prior work had misinterpreted how volcanic rocksrecorded the presence of magnetic fields. For the new study,scientists corrected the error, and for the first time collectedequatorial samples, allowing for a more accurate estimation of theaverage ancient field strength.
This means that eventhough Earth's geomagnetic field is steadily losing intensity, itwill still take around 1,000 years to dip to the newly-definedhistoric average. From this point, it is possible that the field maythen stabilize and maybe even increase in strength. Further studiesare required to better understand the complicated characteristics ofour planet's geomagnetic field, and the potential threat that areversal could pose.
A paper on thediscovery is available online in the Proceedings of the National Academy of Sciences.
Source:MIT
