Where does lightening come from, clouds, ground or both?
Asked by: Jason
First of all, to be vague, it comes from both but starts in the cloud.
A combination of air currents and moving ice and water particles in the cloud
causes positive and negative charges to separate. Put simply, the positive
charges gather near the top of the cloud and the negative charges gather
near the base.
Once an appreciable negative charge has built up on the bottom of the cloud,
a 'shadow' is created on the ground below where a positive charge is
induced. The conditions are now right for a lightning strike.
Once the charge on the cloud is big enough, a small path of negative charge
makes its way towards the ground. Once it gets close, a path of positive
charge leaves the ground and heads up to meet it.
Answered by: Corey Taylor, Undergrad, Florida Institute of Technology
'The strength and weakness of physicists is that we believe in what we can measure. And if we can't measure it, then we say it probably doesn't exist. And that closes us off to an enormous amount of phenomena that we may not be able to measure because they only happened once. For example, the Big Bang. ... That's one reason why they scoffed at higher dimensions for so many years. Now we realize that there's no alternative... '