- Earth’s magnetic field is believed to be produced by the liquid outer core. Outer core produces electric current by convective motion of outer fluidic core which contains mostly molten iron and nickel.
- Rotation of the earth on its axis gives a dynamo effect and magnetic field is produced.
- This magnetic field surrounds the earth and protects it from harmful solar winds.
- If there were no magnetic field around the earth, high amount of solar winds can enters earth atmosphere which results in exit of earth’s atmosphere into space.
- Planet Mars is having no strong magnetic field like earth as its core have no liquid metallic region and hence no dynamo effect.
- Due to this Mars is left with very weak magnetic field which results excessive solar winds interference in its atmosphere.
- Hence its atmosphere exits into the space leaving behind uninhabitable planet.
- Interaction of earth’s magnetic field with solar winds produces Aurora phenomenon. In North Pole this Aurora phenomenon is known as Aurora Borealis and in South Pole Aurora Australis.
- Earth’s Magnetic poles are the point where magnetic field lines of the earth leaves or enter the earth.
- Earth’s Geographical poles are the point where all longitudes meet i.e., at north and South Pole.
- It should be noted that magnetic north and geographical north do not lies on the same point, in other words we can say that axis of magnetic dipole and earth’s rotation axis does not meets and both are separated by 11.30. This angle of variation between magnetic north and geographical north is called “magnetic declination”.
- Magnetic north pole of the earth is located at a point on Ellesmere island in Northern Canada.
- Here it should be noted that there is always a great confusion in the nomenclature of the poles. Lets understand this confusion.
- In case of magnetic bar, magnetic field lines enters from south pole and exit from north pole however in case of earth, magnetic field lines enters from north magnetic pole and exits from south magnetic pole.
- Hence we can say that the magnetic needle which shows magnetic north direction is actually magnetic south and vice versa.
- However convention arose which says that magnetic north is the direction in which north magnetic needle of the compass points.
- This is due to the fact that North Pole of the magnetic needle is the north indicating pole and slowly with time magnetic north is the direction in which North Pole of magnetic compass points.
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