What is lightning?

Lightning is a rapid and huge discharge of electricity in the atmosphere, part of which is directed towards the ground, according to science. The discharges are caused by massive moisture-bearing clouds that reach a height of 10-12 kilometres. The bottom of these clouds is usually within 1-2 kilometres of the Earth's surface, while the top is 12-13 kilometres away. Temperatures in the top of these clouds are in the range of –35° to –45°C.

The dropping temperature causes water vapour to condense as it goes upward in the cloud. The water droplets turn into little ice crystals as the temperature drops below 0°C. They continue to rise, accumulating mass until they are so heavy that they begin to plummet to Earth. This results in a system in which smaller ice crystals move up and larger crystals move down at the same time.

Collisions cause the release of electrons, a process that is remarkably similar to the formation of electrical sparks. A chain reaction occurs as the moving free electrons produce more collisions and more electrons. As a result of this process, the cloud's top layer becomes positively charged, while the middle layer becomes negatively charged.

The difference in electrical potential between the two layers is enormous, on the order of a billion to ten billion volts. A large current, on the scale of 100,000 to a million amperes, begins to flow between the layers in a very short period.

The Earth is electrically neutral, despite being a good conductor of electricity. However, when compared to the cloud's central layer, it becomes positively charged. As a result, roughly 15 percent to 20% of the current is also directed towards the Earth. The destruction of life and property on Earth is caused by this current movement.

Direct lightning hits are uncommon, but given the enormous amount of energy involved, even indirect impacts can be devastating.