Earth's magnetic poles - is a component of the geomagnetic field of the planet, which occurs due to the movement of the molten streams of iron and nickel around a central solid core due to currents in the ionosphere, the local anomalies of the Earth's crust, and others. Magnetic poles recognized the point at which the geomagneticthe field is perpendicular to the surface of the planet.In total there are two poles - north and south, are not antipodal because the asymmetry of the field.
Earth's magnetic poles in the northern hemisphere is inherently southern sincea place where the field lines go under the surface.A "true" North Pole is in the south, where the line from below the surface out.
assumed that the existence of the magnetic poles of mankind knows for a long time.As early as 220 BC in China were made by the first image of the compass, which is called "the heavenly table."It was a small spoon, a rotating plate in the middle of the Bronze Age.The exact coordinates of where the north and south magnetic pole, were installed in the thirties and forties of the XIX century.In 1831, the Ross brothers determined that the North Pole is 70 degrees 5 minutes north latitude and 96 degrees 46 minutes west longitude.A south magnetic pole has the following coordinates: 75 degrees 20 minutes south and 132 degrees 20 minutes east longitude (established in 1841).At the beginning of the XXI century the location of these points has changed significantly.North Magnetic Pole "gone" from the point defined in 1831, to 1340 km, and south - to 1349 km (on location in 1841, respectively).The trajectory of these points is not linear - they can make and return action.
In recent years, scientists have noted that the shift of the magnetic poles of the Earth greatly accelerated.Some attribute this to the fact that in the period 1969-1970.geomagnetic jump occurred which significantly changed the parameters field of the planet.Further adjustment of the location of origin carried out under the influence of shocks of 1978 and 1991-1992.In addition, the magnetic pole of the Earth is influenced by the overall strength of the field, which over the last century has fallen to a minimum value.In this regard, there are suggestions of a possible reversal of the poles when they swapped, causing destruction and numerous natural disasters.Over the past two million years of the change of poles he was held for about 20 times, of which the latter fell on the period of about 0.8 million. Years ago.However, when this happens, the next time to predict accurately, no one can, becauseall previous events were irregular.
During the 1993 study, conducted with the rocks at the bottom of the Pacific Ocean, it was found that the magnetic field reversal after first obtains the maximum charge, then its power is gradually eroding.Perhaps this is some kind of universal mechanism to enhance the protection of life on the planet from cosmic radiation.Without it, our Earth would be a lifeless as Mars, where a very weak field, or Venus, where it is at all.
