The Earth's magnetic axis will not turn over for at least another thousand years, since today its intensity is about two times higher than the average for the last 5 million years.
A drop in the strength of the Earth's magnetic field will not lead to a reversal of the poles in places for at least the next two thousand years, since now its strength is about twice the average values for the recent history of the planet, according to an article published in the journal Proceedings of the National Academy of Sciences …
“I can only say one thing - if the strength of the magnetic field falls at the same rate as today, it will take another thousand years before the point when it falls to typical average values. When this happens, it can go up again and go down. We cannot predict what will happen next, given the extremely unpredictable nature of magnetohydrodynamic processes in the Earth's core,”said Huapei Wang of the Massachusetts Institute of Technology (USA).
Wang and his colleagues came to this conclusion after studying the traces of several ancient flips of the planet's magnetic axis, which "imprinted" in the rocks ejected by volcanoes in the Galapagos Islands over the past five million years.
This archipelago, as scientists note, is an ideal place for such measurements, since it is located almost at the equator of the planet, where the magnetic field strength is always half of those observed at the poles. Similar measurements were carried out by another team of geologists in Antarctica, where many volcanic rocks with traces of a magnetic field also lie.
These observations helped the authors of the article to find out what typical values of the strength of the magnetic field in the past. It turned out that in previous historical epochs the Earth's magnetic field was much weaker than today - about 15 microteslas at the equator instead of the modern 32 microteslas, and about 30 microteslas at the poles, while the modern 64 microteslas.
Previously, scientists believed, relying on measurements of remanent magnetization in rock samples from temperate latitudes, that today the strength of the Earth's magnetic field is approximately close to its minimum values, upon reaching which the planet's magnetic axis usually flips.
The discovery by Wang and his colleagues means that the strength of the Earth's magnetic field today is actually noticeably higher than it was during the past five million years. This suggests that the planet's magnetic axis will not turn over for at least the next thousand years or even longer.
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