"Lightning bolt" could refer to a noise rock band from Rhode Island, a song by an English songwriter, a famous Jamaican track and field athlete or a movie from 1965. Here, we will investigate the scientific phenomenon that inspired one of our prints of the season, dedicated to the sky.
Lightning bolts are massive electrostatic discharges from a cloud to itself – then they are called intra clouds - between clouds or between clouds and the ground. Of course, if you can’t always see them, you can tell they are happening by the sound of the thunder.
Lightning occurs approximately 40–50 times a second worldwide, resulting in nearly 1.4 billion flashes per year.
Lightning's relative unpredictability limits a complete explanation of how or why it occurs, even after hundreds of years of scientific investigation. A typical cloud to ground lightning flash culminates in the formation of an electrically conducting plasma channel through the air in excess of 5 km (3 mi) tall, from within the cloud to the ground's surface. The actual discharge is the final stage of a very complex process. A typical thunderstrom has three or more strikes to the Earth per minute at its peak.
Lightning primarily occurs when warm air is mixed with colder air masses resulting in atmospheric disturbances necessary for polarizing the atmosphere. However, it can also occur during dust storms, forest fires, tornadoes, volcanic eruptions, and even in the cold of winter, where the lightning is known as thundersnow. Hurricanes typically generate some lightning, mainly in the rainbands as much as 160 km (100 mi) from the center.
Lightning is white most of the time when the air is dry, yellow when there is a lot of dust in the air, red when it rains and blue when it hails.
The science of lightning is called fulminology. The fear of lightning is called astraphobia.
Source : http://en.wikipedia.org/wiki/Lightning