But that was not the case. Remember, these conditions normally prohibit cloud formation. If the atmosphere is near saturation , the contrail may exist for sometime. On the other hand, if the atmosphere is dry then as the contrail mixes with the environment it dissipates. Observations, on a continuous and sustained basis since the beginning of 1999, show aircraft as the source of the materials, having been clearly photographed, observed, and documented leaving persistent and continuous trails of an unidentified substance which transforms itself into the 'cloud' formations under the stated conditions of extreme low relative humidity.
Most cloud formations are the result of water vapor accreting around nuclei.
A cirrus cloud model presented by Paul J. Demott, at the Department of Atmospheric Science at Colorado State University deals with laboratory simulations of cirrus cloud processes. The primary variables of the model are temperature, relative humidity, and aerosol size. Special attention should be given to this last variable mentioned. This source states that the material being delivered by aircraft is composed of barium salts, and that it is being used in connection with advanced radar studies. Barium oxide is a whitish powder.