what is lightning ??   i want a long answer please

 

Lightning is a powerful natural electrostatic discharge produced during a thunderstorm. Lightning's abrupt electric discharge is accompanied by the emission of light. The electricity passing through the atmosphere rapidly heats and expands the air, producing lightning's characteristic thunder sound.

The first process in the generation of lightning is the forcible separation of positive and negative charges within a cloud or air. Polarization mechanism - This mechanism has two components: the first is that falling droplets of ice and rain become electrically polarized as they fall through the atmosphere's natural electric field, and the second is that colliding ice particles become charged by electrostatic induction. Once charged, by whatever mechanism, work is performed as the opposite charges are driven apart and energy is stored in the electric fields between them. The positively charged crystals tend to rise to the top, causing the cloud top to build up a positive charge, and the negatively charged crystals and hailstones drop to the middle and bottom layers of the cloud, building up a negative charge. Cloud-to-cloud lightning can appear at this point.

For cloud-to-ground lightning, a second process occurs. Positive charges appear on the ground beneath the clouds, and electrical energy is stored in an intense vertical electric field between cloud and ground. The earth is normally negatively charged with respect to the atmosphere. But as the thunderstorm passes over the ground, the negative charges at the bottom of the cumulonimbus cloud cause the positive charges on the ground to gather along the surface for several miles or kilometers around the storm and becomes concentrated in vertical objects including trees and tall buildings.