lightning

Click a letter for the index

Or search the encyclopaedia:

 

 

Go

 

Click images to enlarge
High-voltage electrical discharge between two rainclouds or between a cloud and the Earth, caused by the build-up of electrical charges. Air in the path of lightning ionizes (becomes a conductor), and expands; the accompanying noise is heard as thunder. Currents of 20,000 amperes and temperatures of 30,000°C/54,000°F are common. Lightning causes nitrogen oxides to form in the atmosphere and approximately 25% of atmospheric nitrogen oxides are formed in this way.

According to a 1997 US survey on lightning strength and frequency, using information gathered from satellite images and data from the US Lightning Detection Network, there are 70–100 lightning flashes per second worldwide, with an average peak current of 36 kiloamps.

White stands for Islam, peace, optimism, light, and love. Red recalls the martyrs of Sudan and the people's struggle. Black stands for Sudan and the Mahdiya revolution of the 1880s. Effective date: 20 May 1970. >>