What is ball lightning? How is it different from usual lightning?

As its name should imply, "The mysterious ball lightning" is a spherical lightning ball. It is absolutely not an energy explosive that appears in science fiction or cartoon, but a physical phenomenon in reality. There has been historical account recording this phenomenon since 1838. Scientists has been researching into this phenomenon for over 160 years, so there are thousands of associated reports and about 2 thousands published scientific theses. However, we still have not obtained a reasonable explanation on this phenomenon.

The mysterious ball lightning usually occurs under thunderstorms. It is very bright, spherical and with a diameter of about 20 to 50 cm. Usually it lasts for a few seconds only, but there is also some records showing that it has lasted 1-2 minutes. Miraculously, it is able to move independently and slowly in air. Some witnesses claimed that it moved with the metallic substances, such as telephone wires. Majority of witnesses, however, said that its routes were uncertain. Besides they mostly said that it moved horizontally. In its short life of a few seconds, its brightness, shape and size remain constant. It used to appear on an open ground, in a sealed room, and even on an airplane! There is some signs indicating that it has a close relationship with the usual lightning that formed between the cloud cover and the ground, as it is witnessed that it would develop or disappear after usual lightning. It may explode violently, while it may also disappear suddenly. About its color, opinions are widely divided so there is no common description.

The mysterious ball lightning has certain extent of destructive power as natural lightning does. It is able to destroy windows with glass, and peel off the coating of walls. Furthermore, it used to cause death to the animals and the human beings. However, the actual cause of killing was not known because of insufficient data. On the other hand, there is no evidence showing that ball lightning will destroy trees. This is different from the usual lightning.

Due to the rare occurrence of ball lightning, the scientists cannot have a systematic observation of it. In the meanwhile, there have not been any high quality photos for research yet. For theories, some people believe that ball lightning is made of lumps of hot air or vaporized elements such as carbon, sodium or copper. This theory can explain part characteristics of ball lightning, but it fails to explain why ball lightning can develop on airplanes. There are many other theories, e.g. plasma, ions, charged dust, water cover with a shell of electrons, etc., but none of them can fully explain this mysterious, unsettled case of science. So if you have ever seen ball lightning, or have taken photos of it, you should make a detailed record. It will be valuable data for research.