For the 30. January have decided to geophysicists from the US and the UK to an unusual, for the whole world an important step: you update in advance of the “World Magnetic Model”, the world magnetic model. If they did not, it would pilots, ship captains, and even users of Google Maps have a look soon to be stupid, if your GPS fails.
works Because it is only thanks to the magnetic model, the precise Navigation by compass. It is the magnet describes field of the earth. About how the North magnetic pole to the geographic North pole. Because the two are not identical. On the contrary, The magnetic North pole – the place, where the field lines of the earth’s magnetic field collide perpendicularly in the earth, located several hundred kilometres from the geographical centre. And he wanders. In the last few years, even faster. He no longer wanders, he runs.
magnetic poles are not exactly opposite
the earth’s magnetic field is important for all life. It protects us from deadly radiation from space. And some of the animals it serves for the orientation – since we have invented the compass, for us humans, too. Since we nowadays want to navigate on our travels around the globe but right exactly, scientists have developed the world magnetic model. So we not only know about, but just where North is.
describes the model, where the magnetic poles are, but also how the magnetic field lines extend, in which the compass aligns. Because their network spans the globe from the North to the South pole, is by no means symmetrical. The magnetic poles are not exactly, you can walk in step. And the power of the field lines has dents: they do not run anywhere in a straight line, the field strength at some Points weaker than elsewhere.
This has to do with the cause of the magnetic field: It arises due to movements in the earth’s Interior. From the solid, up to 5000 degrees hot core of iron and Nickel increases heat and results in the outer, liquid core is also mostly iron, ocean currents, Convection. The Material penetrates to the outside, cools down again and sinks in a circuit back into the deeper layers. Due to the rotation of the earth, it also comes to lateral movements. And because the Material is electrically conductive, forms the magnetic field around our home planet.
Since the 90s of the North pole travels 50 kilometers per year
“The circulation one can water imagine like cooking in a pot,” says Achim rotten Hauser, a researcher at the geomagnetic Observatory Niemegk of the GeoForschungsZentrum (GFZ) in Potsdam “The heat rises from the bottom and keeps everything in motion. And to these movements, the magnetic field lines are coupled. Like Spaghetti, you throw in the boiling water, also be moved on an ongoing basis.”
It is a dynamic System with many irregularities in the movements alternate with counter-movements. In the extreme case, it even comes to a complete pole reversal: The magnetic North pole becomes the South pole and Vice versa. Actually, the North pole is currently the magnetic seen are actually a South pole. On average, every 250,000 years, as analyses of magnetized iron particles in ancient layers of rock. The last reversal of the earth’s been 780.000 years – the next one appears so overdue.
Perhaps the frenzy of the North pole is even a harbinger of this. While he was in the course of the 20th century. Century put ten to 15 kilometres per year and from the North of Canada in a relatively straight line through the Arctic ocean towards East Siberia migrated, it has accelerated since the 90s, to about 50 kilometers per year. The must, however, have no polarity. Some researchers also believe that the reason for his hurry in a more than 400-km-wide horizontal stream of liquid iron, you have discovered two years ago, 3000 kilometers in Canada and Russia, and is a good 40 kilometers per year in the direction of Europe – three Times faster than the Material in the outer core of the earth usually flows.
About the Interior of the earth, little is known
“Theoretically, the Pole can change its direction of movement but also, at any time, as he did in the 19th century. Century has to be done,” says Achim rotten Hauser. “Therein lies the Problem: We know the convection currents in the earth’s core is too little, such effects are to predict.”
Actually, the research on the Interior of the earth knows still less than that of the sun. Similar to unpredictably so-called geomagnetic impulses can occur relatively sudden peaks in the circulation in the earth’s core. How extra-large bubbles in a cooking pot, these outbreaks provide strong disturbances of the geomagnetic field.
Other distortions are of longer duration: for almost 200 years, – Alexander von Humboldt, the noted at the time, we know that the magnetic field over the South Atlantic, including South America and South Africa, is particularly weak. Satellites flying over this Region, but also living creatures on the ground are subjected to increased radiation from space. Experts call this the “South Atlantic anomaly”. Similar to the acceleration of the North pole also, you could announce a reversal. You don’t have to. Often recovered in the magnetic field of such periods of Weakness.
Normally, the model is updated only every five years
in any case, such effects lead to the geophysicists to update your model well in advance. Normally, you do that every five years: The model describes the current state and calculates, as the field is developed in the following years – where, for example, the North pole will move. Researchers use measurement data from satellites and ground-based observatories, which are distributed over the whole globe.
“But the projections are linear,” says rotten Hauser. “If there is a short-term anomaly comes up, not the forecasts.” In 2016, only a year after the researchers had updated your model least, that was South America, a strong geomagnetic pulse, which makes the actual development of the prediction deviate. “Since then the error has become larger,” says Arnaud Chaulliat from the University in Boulder, Colorado, working on the world magnetic model, the journal “Nature”.
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Ralf Nestler
Now it’s reached the threshold of tolerance. The person responsible for the world magnetic model must act. Otherwise, the deviations in the Navigation are so great that a Pilot from the USA would end up with a TRANS-Atlantic flight by compass bearing instead of in Berlin, perhaps in Luckenwalde.
