Does Earth Have Electric Field? 7 Facts You Should Know


A space around charged particles gives a physical field called an electric field. If the earth is treated as a charge, then let’s discuss the electric field surrounding the earth.

Earth has an electric field. Earth’s inner core contains metals in a molten state. The flow of the liquid metal generates a conventional electric current in the core which is evident in the electric field of the earth.

The electric field of the earth is always pointing vertically downward at the surface. Let us provide some more facts on when, and how the earth has an electric field in this post.

 When does the earth have an electric field?

The consequences of earth’s electric field are associated with the discharge of charged particles in space. Let us focus on the existence of an electric field on the earth.

Earth has an electric field when the air is ionized due to the irradiation of cosmic rays which carries charged particles. The existence of the electric field on the earth associated with air ionization creates spatial separation of positive and negative charges in the atmosphere.

The ionized air discharges the electrical charges in the atmosphere creating ionosphere for the earth which acts as shield. The thunderstorms also discharge electric charges in the air which also created an electric field on the earth.

Electric field generated at the ionosphere
Image credits: Wikimedia commons

Is the electric field same everywhere?

The electric field generally originates from the time-varying electric current. Since current can vary, let us know whether electric field is same at every point.

The electric field cannot be the same everywhere. Because according to Coulomb’s law, the force exerted between the charges can vary with distance. Since the electric field describes the force on the charges, this field changes as the distance changes.

Another evidence for unequal distribution of electric field is poles of the earth. At both the poles of the earth, intensity of electric field is more because large amount of cosmic radiations strike at the poles, thus discharge of charges is more at the poles and hence electric field is more comparatively other region.

Why does earth have electric field?

 The electric field of the earth is the short-distance field and it is generated by dynamic phenomena. Let us find the motive of electric field of earth.

Earth has an electric field because of interior mantle ions and cosmic ray irradiation. The inner core contains of a huge amount of metal which has free electrons which produce an electric field. The cosmic rays entering the earth at the pole consist of charged particles contributing for the electric field.

Other phenomena such as human friction, object buildup charges, and clouds, thunderstorms can also cause an electric field of the earth. But this electric field of the earth is not continuous. The electric field generated by the metal ions in the crust is the reason for the generation of magnetic fields on the earth.

Is Earth charged positively or negatively and why?

Number of protons and electrons specifies the object as positive or negatively charged. Let’s discuss whether earth is positive or negatively charged as a single charge.

Earth is neutral as a whole because it carries both positive and negative charges in an equal ratio. According to the charge-neutrality principle, the surface of the earth is negatively charged and the inner part is positively charged which gets canceled out, so the earth’s total charge is zero.

The extreme high temperature and pressure of inner core makes the atom to ionize and hence creates the hole carrying the positive charge. However, air above the surface in the atmosphere is positively charged.

How much electricity is in the ground?

Ground is electrically positive and it can easily attract the negative charges from the surface, so let us know amount of electricity in ground.

The ground consists of 0V of electricity. When the negative charges from the surface enters the ground, both positive and negative charges canceled out, so that no electricity can flow in the ground. About 1800amp of current reaches the earth surface but they are not sustained in the ground.

The negative terminal of the wiring of the building is connected to the ground for safety purpose because the ground can accept negative charges and prevent excess electric flow.

 Why does current flow to earth?

The flow of current is associated with the flow of available free electrons in the given material. So, let us find the reason for current flow in earth.

Earth is attractive place for current flow because ground is positively charged and the atmosphere consist greater number of negative charges. The negative charges are the source for current flow. Due to atmospheric collision with the negative charges, the current flows to the earth.

Where does electricity go from earth when not used?

Electricity is also an energy that neither is created nor destroyed even when it is not used. So, let us know about unused electricity in earth.

The electricity will remain in the earth even if it is not used. The electricity will remain in the free electrons as energy and dissipate in the air. This electricity travels between cloud and ground through air to maintain the earth as electrically neutral.

The concept of atmospheric electricity begins with the above mentioned ideology. The electric charges keep moving between surface of earth, atmosphere and ionosphere forming global atmospheric electric circuits. Sometimes the charges collide with other charged particles in the atmosphere.

Conclusion

Let us end this post by stating electric field of the earth is similar to the magnetic field of the earth but only difference is electric field of the earth is not continuous. The discharge of electrical charges during lightning is also a reason for the existence of an electric fields on the earth.

Keerthi Murthi

I am Keerthi K Murthy, I have completed post graduation in Physics, with the specialization in the field of solid state physics. I have always consider physics as a fundamental subject which is connected to our daily life. Being a science student I enjoy exploring new things in physics. As a writer my goal is to reach the readers with the simplified manner through my articles. Reach me – keerthikmurthy24@gmail.com

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