The magnetic field of the earth protects us and gives orientation to migratory birds – but it changes. A study now shows that the poles can change their polarity much faster than expected.
By Gabor Paal, SWR
The magnetic field of the earth protects us from cosmic radiation and solar wind. It gives orientation to migratory birds and shows us per compass where there are north and south. But nothing has been solved. The magnetic poles wander off and in the past the magnetic field of the earth has repeatedly collapsed or even reversed. This can be proven well in magma rock.
Many geophysicists are convinced that the next pile shift is already underway. Even if there are voices against, they keep the hints clear.
Earth's magnetic field has decreased by ten percent since measurements began 175 years ago. The magnetic pole moves faster and faster. Today it is located under the Arctic ice north of Canada – but every year it floats more than 50 kilometers to Siberia, more than three times as fast as a hundred years ago. Third argument: it is high time. On average, there is a pool shift every 200,000 to 300,000 years. But the last one is already 780,000 years ago. The next pole shift would be too late.
Polar reversals faster than expected
Short-term pole reversals are even more common and can happen faster than previously thought. This possibility suggests at least a new study from China. Thus, at the beginning of the last ice age, the North and South Pole changed party to the earth in just 144 years. So far, researchers have assumed that such a pool change takes several hundred years.
Researchers have measured the variations in the magnetic field in stalactites of Chinese limestone caves. The advantage: even in stalactites – here stalagmites – a magnetization can be detected and they match very well with the age of the stalactites.
Short-term attenuation of the magnetic field
The event that the researchers examined was about 98,000 years ago. At that time, Neanderthals already lived in Europe. At that time it was not a real pole shift, but only a so-called "excursion", a short-term attenuation of the magnetic field, within which it also came to a short-term pole reversal – just before the magnetic field almost collapsed.
This observation suggests that even today polar reversal can take place quickly – especially when with the present weakness of the magnetic field there is only one result and no real pole jump.
"Results of the high-quality study"
Jürgen Matzka of the Geo Research Center in Potsdam thinks that this is quite possible: "Such excursions are ten times more common, but in the initial phase they can not be distinguished from real pole jumps." Matzka was not involved in the Chinese study, but finds it very well: "The researchers have made full use of the relatively new stalagmite method, the results are of high quality."
Years ago, studies were published that appeared to be a much faster pile wrap within a few years. But these were methodically heavily criticized.
How the magnetic field of the earth is polarized & # 39; is, does not matter for life on earth. It's about how strong it is – or how weak it is. Whether a real pole shift is imminent or "just" an excursion, the effects would be the same.
There is no reason for panic
Even our early ancestors survived the weaknesses of the "Geodynamos". In addition to the magnetic field of the earth, the atmosphere protects us from aggressive radiation and particles from space. However, the situation is different for satellites: they are attacked much more strongly in the case of a weak geomagnetic field. Especially the geostationary radio and communication satellites would be less protected.
A weak magnetic field and a renewed thinning of the ozone layer are threatening in the higher atmosphere. At least at the poles exposure to UV rays could increase. And migratory birds can also be hindered by a weaker magnetic field.