In a 8 Nov 2017 article in The Conversation, Christopher Davies,
a research fellow in geophysics at the University of Leeds, writes of
a mysterious geomagnetic "spike" in the Earth's interior that took
place 3000 years ago.
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Originally Posted by Christopher Davies
The Earth’s magnetic field, generated some 3,000km below our feet in the liquid iron core, threads through the whole planet and far into space – protecting life and satellites from harmful radiation from the sun. But this shielding effect is far from constant, as the field strength varies significantly in both space and time.
Over the last century, the field strength has changed relatively slowly: the biggest change is a 10% fall in the southern Atlantic, which is still a large enough effect to cause electronic problems for satellites that have passed through the region. However, new observations and modelling suggest that a much greater change strangely occurred around 1000BC in a much smaller region.
This “geomagnetic spike” offers a potentially profound new insight into the dynamics and evolution of Earth’s hidden interior that is now starting to be uncovered.
So what are geomagnetic spikes and what are the prospects and implications of another one coming along? The geomagnetic spike of 1000BC was first identified from copper slag heaps located in Jordan and Israel. These were dated from organic material within the slag heaps using radiocarbon dating.
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Geomagnetic storms
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Originally Posted by Christopher Davies
Geomagnetic storms tend to be most prevalent in regions where Earth’s magnetic field is unusually weak. Spikes are regions of unusually strong magnetic field, but a fundamental law of nature means that they must be accompanied by regions of weaker field elsewhere on the globe. The key question is whether the field gets a little bit weaker over a large region or becomes very weak in just a small region. The latter “anti-spike” scenario could be similar to or more extreme than the current south Atlantic weak spot.
Whether there will be more spikes is hard to say.
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Article here :-
https://theconversation.com/mysterio...interior-86638
