This visualization of the Earth’s core shows how turbulent waves (shown in red and blue) twist-up of the planet’s magnetic field lines (orange) in the pockets of intense activity. This mysterious phenomenon called a geomagnetic jerk.
(Aubert et al./IPGP/CNRS Photo library)
Earth’s magnetic shield that defends our planet from the threats of the health of the solar wind and cosmic radiation, allowing life on our planet possible. But every 10 years or so, it can be a real jerk.
“Geomagnetic jerks” are abrupt changes in the strength of the magnetic field of the Earth. While some variations in this area are expected to occur gradually, over a period of hundreds to thousands of years , these sudden fluctuations in intensity last only a few years, and can only change the magnetism of the Earth over specific parts of the world at the same time. One of the first shock is documented, for example, in the short warped the field across Western Europe in 1969.
Since then there has been a new jerk is detected somewhere in the world every 10 years or so, and scientists still do not know what the cause is. While many geomagnetic phenomena, including the northern and southern lights, result of an electrified solar wind-bashing in the magnetosphere of the Earth, the acorns are believed to originate from deep inside our planet’s core, where the magnetic field itself is generated by the constant churn of the liquid-hot iron. The exact mechanism of action, however, remains a mystery. [The 8 Biggest Mysteries About Planet Earth]
Now, a new study published today (22 April) in the journal Nature Geoscience offers a possible explanation. According a new computer model of the core physical conduct, geomagnetic shocks can be generated by the buoyancy of spots of molten matter released from deep in the core.
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Who is that jerk?
In the new study, the researchers built a computer model that accurately reconstructs the physical conditions of the Earth’s outer core, and shows the evolution over several decades. After the equivalent of 4 million hours of calculations (accelerated thanks to a French supercomputer), the core of the simulation was able to generate geomagnetic jerks, which are closely aligned with the actual shocks observed in the past decades.
These simulated shocks jiggled the magnetosphere every 6 to 12 years in the model — however, the events seemed to originate from upward deviations that arise in the planet’s core 25 years earlier. If those flecks of melted matter approached the outside of the core, that powerful waves that rush along the magnetic field lines in the vicinity of the core, and made “sharp changes” in the stream of the liquid applicable on the planet of the magnetosphere, the authors wrote. Ultimately, these sudden changes are reflected in the feet manifested as shocking disturbances in the magnetic field, high above the planet.
“[Jerks] constitute a major obstacle for the prediction of the geomagnetic field behavior for the years to decades ahead,” the authors wrote in their new study. “The ability to numerically reproduce jerks offers a new way to measure the physical properties of the Earth’s deep interior .”
Although it is impossible to confirm this, simulation results with actual observations of the nucleus (it is too hot and high-pressured to be anywhere near the planet center), having a model that can recreate historical shocks with a high accuracy can be helpful in predicting the many shocks still to come, the researchers wrote.
Know where the acorns are coming to expect from an acorn can also help control and understand how they impact on other geodynamic processes. For example, it is possible, as one 2013 study in Nature suggested that the acorns are harbingers of longer days? According to that study is that researchers, sudden changes in the flow at the Earth’s core can also be an effect of the planet spinning by the slightest bit degrees, actually adding an extra millisecond to the day, every six6 years or so. Periods in which one Earth day is extended, seemed to correlate with a number of established cases of well-known shock, the researchers reported.
If that is true, and geomagnetic jerks are responsible for a longer working day, every couple of years, at least we know that we have the correct name.
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Originally published on Live Science.