The approximate range of the earth’s atmosphere is near about 400km. On the basis of some certain properties the earth’s atmosphere is divided into four simple categories.
These are mesosphere, troposphere, stratosphere and ionosphere. Properties of earth’s atmosphere are given below:
1. The conductivity of earth increases as we go higher and higher in the space. The atmosphere present near the surface of earth is a bad conductor of electricity. The best part of our atmosphere which acts as an awesome conductor is the ionosphere of earth. The ionosphere is good conductor due to the ionization of the molecules. The ionization is done by the cosmic rays present there. These rays are very high energy rays having energy of 1014 MeV.
2. Earth has a totally balanced potential. It is so because earth is a good conductor of electricity.
3. On the surface of earth the value of electric field E is 100V/m. On the whole earth the direction of the electric field is towards the center of the earth i.e. in the downward direction. As we go higher the magnitude of electric field will decrease. At a distance of nearly 10 km from the surface of earth the electric field becomes very less. Near about 50 km away from earth in the upward direction, its value becomes negligible.
4. The value of the potential difference between the earth’s surface and the extreme top of the stratosphere is near about 4 X 10 5 V. When we will discuss this fact then we will observe that the top of the stratosphere and the surface of earth near about at a distance of 50km from the surface are forming a spherical conductor.
The capacitance of this spherical capacitor can be measured with the help of the formula given below:
C= 4 
r a rb / (ra – rb)
ra in the above equation is the radius of the earth. Radius of earth is approximately 6400km.
We can write it as 6.4 * 106m
and rb is the radius of the stratosphere 6450 km=6.45 * 106m.
After substituting all the values in the above equation we get
C= 0.1 Farad.
5. A regular current flows under the surface of earth. It is due to the downward direction of the electric field of earth. The current density of the earth which is passing under the earth’s surface is 3 * 10-12 C/sec/m2. But the surface area of earth is:
4 (6.4 * 106) * (6.4 * 106) m2
After calculation the result will be 1800 coulomb.
It means earth can take near about 1800 coulomb of charge per second. So, it is a huge amount of charge. In other words as a whole we can say that earth can take unlimited charge.
