Components of the Magnetic Field of Earth

Earth’s magnetic field, otherwise also called a geomagnetic field, is a magnetic field that is associated with planet Earth. This magnetic field spreads from the interior of the Earth to the space above. In outer space, it proceeds to interact with the solar winds and charged steam particles that are given out by the sun. The Earth’s magnetic field is composed of currents of electricity. These currents are caused due to the motion of convection currents of a molten mixture of the elements – iron and nickel that are present in the core of the Earth. The heat that flees from the core of the Earth is the source of the convection currents. This is a natural process which is called geodynamo. The magnetic field of the Earth has a magnitude between 25 to 65 𝝻T or 0.25 – 0.65 G. The two properties of the Earth’s magnetic field are: they never intersect or cross each other and they pass from the north pole to the south pole.

Significance 

• The solar winds and charged steam particles from the sun are deflected by the Earth’s magnetic field. If these particles are not deflected, they would deteriorate the Earth’s ozone layer which protects the Earth from the harmful ultraviolet rays. 

• Palaeomagnetism is the study and research associated with the Earth’s magnetic field. In igneous rocks, the polarity of the magnetic Earth is recorded. Hence, the reversal of the field is detected in the form of stripes on mid-ocean ridges where the seafloor spreads. The basis of magnetostratigraphy is the reversal of the magnetic field. Magnetostratigraphy is a process of dating sediments and rocks. 

• The magnetic field of the Earth is responsible for magnetising the crust and other anomalies of magnets are helpful in detecting deposits of metal ores. 

• Magnetoreception is used by many organisms, animals, and even humans for navigation and orientation purposes. 

Earth’s magnetic field: components 

The following table showcases the important components of the magnetic field of the Earth.

Apart from D and I, the other elements are measured on a scale of nanotesla. D and I are calculated in degrees.

The three predominant components that are in charge of the Earth’s magnetic field – the magnitude and direction are:

• Magnetic declination 

• Magnetic inclination 

• The horizontal components 

Magnetic declination (represented by D) 

It is also known as the magnetic variation. It is the angle that is measured between the magnetic north direction and the true north direction on a horizontal plane. The true north direction is directed along the meridian that is towards the geographical north. The magnetic north direction is the direction that is given by a magnetic compass. The value is expressed in degrees. The declination is considered positive when the magnetic north is along the east side of the north true north. It is considered negative when the magnetic north is towards the west of the true north. It is expressed by the term D. 

Magnetic inclination (represented by I)

It is also known as a magnetic dip. It is the angle measured between the horizontal plane and the vector of the magnetic field. This angle differs depending on the location of the Earth’s surface. By convection, the inclination value is positive when the Earth’s magnetic field points towards it. If the direction of the magnetic field is upwards, it is negative. This dip occurs due to the result of the tendency when a magnet aligns with the magnetic field lines. It is represented by the term I. The magnetic dip at the equator is measured to be 0 degrees. The magnetic dip at both the magnetic poles of the Earth is measured to be 90 degrees.

Horizontal components

Two horizontal components help to elucidate the Earth’s magnetic field.

• Vertical component – It is represented by the letter V.

• Horizontal component- it is represented by the letter H.

Conclusion

The Earth’s magnetic field is a magnetic field that is associated with planet Earth. Otherwise also called a geomagnetic field. The field spreads from the interior of the Earth to the space above. In outer space, it proceeds to interact with the solar winds and charged steam particles that are given out by the sun. Palaeomagnetism is the study and research associated with the Earth’s magnetic field. The three predominant components that are in charge of the Earth’s magnetic field along with the magnitude and direction are magnetic declinations, magnetic inclination, and the horizontal components of the Earth’s magnetic field.