Lightning is formed due to a string of occurrences in the sky. There is a lot of curiosity among us to know why and how is lightning formed. Also, there is an ongoing argument over its formation. Lighting occurs when electric charge is formed in the clouds. There are many theories that suggest how lightning is formed; the most accepted one is polarization mechanism.
There are instances like intense forest fires, volcanic eruptions and surface nuclear explosions when lightning can be observed apart from thunderstorms. Positive and negative charges are generated during thunderstorms and when these separate, energy is released in the form of lightning. The process starts with the development of ice in the cloud.
In thunderstorms, these ice particles crash into one another and this clash creates the electric charge in the cloud. When this electric charge intensifies, electrons are pushed farther down on earth. This half portion of the cloud has a negative charge and the surface of the earth carries a positive charge, which is very strong. This situation when electric charge is formed between earth and the cloud leads to the formation of lightning.
Lightning travels via a path that is curved, which is why it never appears to be straight. The pathway has bends because dust particles in the air breaks down the air. Lightning can pass after ionization of air between the earth and the cloud. When the lightning neutralizes the earth, air and the cloud, it will not hit again.
Lightning can be highly dangerous sometimes. If a lightning is formed in the top of the thunderstorm, it carries the positive charge from there to the ground, which has negative charge. This is highly dangerous as it might travel 5 to 10 miles ahead of the stormy area, which people might consider safe. This kind of positive lightning transfers great electricity charge to the ground for a longer period of time. In such cases, there is a possibility of forest fires as well. Aircrafts are also at the risk of being damaged by positive lightning. Lightning might just look like a streak in the sky but it has much more to it.
