What is geomagnetism?
It is the study of the earth's dynamic magnetic behavior, their sources, advantage, and impact of the magnetic field shift.
Earth magnetic field:
Our earthworks as a giant bar magnet. Earth is surrounded by vast areas of the magnetic field is called the geomagnetic field.
Bar Magnet:
It is a simple magnet that is made up of usually ferromagnetic material such as cobalt, Iron, Nickel and has a magnetic field around it.
The following are the main features of the earth magnetic field:
- The intensity of the magnetic field of the earth is not the same all over the earth, both poles have an intense magnetic field than the equator.
- A hypothetical, giant magnetic dipole is located at the center of the earth.
- Axis of magnetic Pole is not the same with the axis of rotation of earth or geographical axis. Axis of a magnetic dipole is tilted by 11.3 degrees from rotation axis or approx 78 degrees from the orbital plane.
- Poles near to geographical north poles are called north magnetic poles.
- Poles near to geographical south poles of the earth are called South magnetic poles.
- Magnetic field line goes into the earth at north magnetic poles and came out from South magnetic poles.
- There is reverse dipole the earth that means north magnetic poles behaves like south magnetic poles of bar annual inside the earth.
Sources of earth magnetism:
Exact sources of earth magnetism are not known, however, the following may be the reason of origin of earth magnetism:- The magnetic field of the earth is arising due to the flow of electric current in the outer core of the earth that is generated by rotating metallic fluid of iron and nickel. This is known as dynamo effects.
- In the outer layer of earth atmosphere that is the ionosphere. Various gases are in the ionized state in the ionosphere due to rotation of the earth about the axis, the strong magnetic field is set up by charged ion.
Earth magnetic dipole is not static:
- Earth's magnetic field is dynamic in nature, the location of the magnetic north and south changes from time to time and it also gets reversed.
- At present, the magnetic north is shifting 9 km per year eastwards, from Canada towards Russia. Shifting speed is not the same, sometimes it shifts around 50 km per year.
- Paleomagnetism study gives proof about the shifting of the earth's magnetic field.
- Paleomagnetism is the study of the record of earth magnetic field in rocks.
- During rock formation time, the same magnetic properties of the earth such as magnetic north and the south pole are being recorded in rocks.
- The study of magnetic properties of different times of rocks can give information about the shifting direction of the earth's magnetic field.
Advantage of earth Magnetic field:
- The geomagnetic field saves the earth from harmful sun flares. The harmful sun winds can damage the earth's life, if not blocked. Some of Sun particles are able to enter earth poles which can be seen as light sower or light aurora Borealis.
- It helps in navigation by Compass
- Some animals such as migratory birds use earth magnetic fields to direction and navigation.
- If earth core ever cooled than the magnetic field will be disappeared and earth will be like the moon.
The following are implications of shifting magnetic field:
For Explanation, please watch the below videos:- Shifting the magnetic field would hamper surveying, communication techniques, and spacecraft.
- Location of magnetic north and south changes.
- The location of the light sower or light Aurora or Borealis will changes.
- Some magnetic bird uses magnetic field direction for findings the way. Shifting magnetic direction will confuse the path of birds and they may be lost the path.
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