1 Ball lightning is an objective phenomenon that in most cases has the unique physical nature.

 2 The typical size of the ball lightning is from 10 to 20 cm. The life time is from several seconds to several minutes.  (The life time is related to the diameter, namely, on the average, it increases with the increase of diameter).

 3 Visible light emitted by a ball lightning does not belong to one particular spectral band, although the red end of the spectrum is observed most often. The emitted power by  the ball lightning of a medium diameter is of the order of  0,1 to 0,01 W.

 4 The heat emission power is not greater  than 0,5 to 1 kW. The temperature is seemingly not higher than  200 to 300 C.

 5  The ball lightning seems to give noise in radio band. However, there are no evidences of its relation to the emission of electromagnetic waves with wave length shorter than that of the visible light  (or, at  least, not shorter than for near ultra-violet).

 6 The average density of the ball lightning substance  is about 1,5 to 2 times greater the air density.

 7  Ball lightning is capable of maintaining and recovering a spherical shape. Under decay, each part tends to take the spherical shape again. On the ball lightning surface, elastic oscillations (surface waves) are observed.

 8 Rather interesting, and not mentioned earlier, is the  ball lightning ability to excite pulses of current when contacting with conductors.

 9 What is usually called the ball lightning "explosion" represents a short term discharge of the objects and parts of the earth surface electrified during the thunderstorm.

 10 The ball lightning usually  arises from the conductors carring a big electrical charge, during the thanderstorm.