Scientists know that our planet for thousands of years has repeatedly changed the direction of the magnetic field is reversed.
Imagine that some 800 000 years ago, if we were with a compass in the hands of the person to what is now called the north, the arrow pointing to the "south". This is because the magnetic compass is calibrated to the direction of the Earth's poles. If the polarity of the magnetic field has changed today, to mark the compass "N — S" deviated to 180 degrees.
Doomsday theorists are trying to prove that it is a natural geological phenomenon can lead to the death of the Earth. How justified are their concerns? Let's try to understand.
Reversal of the magnetic poles (inversion) — rather, a pattern, rather than the exception. Over the past 20 million years, these changes have been occurring every 200-300 thousand years. Some scientists believe that the Earth is long overdue moment of reversal of the magnetic field, but no one can say for sure when it's just going to happen. Inversion can occur for a hundred or a thousand years, and not necessarily just for all 180. Sometimes in the course of this process there is a set of poles at random latitudes.
In the deep sediment cores taken from the ocean floor, captures the activity of the magnetic polarity of the planet. They can be used to determine the residual magnetization of rocks. When the lava cools after a volcanic emissions and freezes, it "fixes" the direction and intensity of Earth's magnetic field at the time. The last time the poles are reversed 780 thousand years ago. This phenomenon scientists called Gauss-Matuyama reversal. Paleomagnetic analysis of bottom rocks of the Mid-Atlantic Ridge, where the cost of the North American and European tectonic plates, showed that no extraordinary changes in the flora and fauna not. Amount of oxygen isotopes in sediment cores of this period also indicate that glacial activity remained unchanged. Thus, the change does not affect the polarity of the Earth's axis, the slope of which has a significant effect on climate and glaciation processes.
Thus, the polarity of the Earth — not a constant. Unlike conventional or souvenir magnet on our fridge, a matter, which controls the magnetic field rotates. Geophysicists believe that the Earth's magnetosphere is there because the solid iron core surrounded by an ocean of liquid hot metal. This process can be modeled using a supercomputer. Our planet, without any exaggeration, is very dynamic. The flow of liquid iron in the core produces an electrical current, which in turn generates a magnetic field. Since the Earth's outer core is located too deep for direct measurements, scientists can try to change it, watching the activity of the magnetic field. Since the beginning of the 19th century, when scientists first identified the precise location of the magnetic North Pole, he moved towards the north for more than 1100 km. Now it is moving faster. Scientists estimate that the pole migrates at a speed of about 64 km per year, whereas in the early 20th century — 16 km.
Another apocalyptic hypothesis predicts geomagnetic changes the world the horrors of the approaching solar activity. It is a misconception that because of the shift of the poles on Earth disappears instantly magnetic field protects us from the prominences and coronal mass ejections. The Earth's magnetosphere can be relaxed or strengthened over time, but there is no evidence that it was once completely disappeared. Weaker field, naturally, leads to a slight increase of solar radiation on the Earth and auroras at lower latitudes, but nothing catastrophic about it. Even with weak magnetic field atmosphere may provide protection against invading particles of the sun.
Scientific observations show that the change of the magnetic pole in the context of the scale of geologic time — a common phenomenon that occurs gradually over thousands of years. Despite the fact that the conditions of polarity is not completely predictable, for many millions of years of geological history of our planet is not fixed any evidence indicating that the predictions of the Apocalypse in 2012 should be taken seriously.