have read the letters and reviewed the referenced web pages . In so doing, I have viewed a number of photos purporting to be of aircraft spraying the chemical or biological material into the atmosphere.Judging from photos alone is not sufficient to tell the difference. But if they really an expert they should notice anomaly like mentioned bellow:
In summary, there is no evidence that these "chemtrails" are other than expected, normal contrails from jet aircraft that vary in their shapes, duration, and general presentation based on prevailing weather conditions.
"Contrails are frequently visible at distances as close as 25-35 m behind the aircraft engines. Using an analytical model of ice crystal growth in the exhaust plume, showed that the number density of ice crystals nucleated must be at least about 104cm-3 in order for the contrail to be visible this quickly...... The simulations suggest that fleshly nucleated sulfuric acid/water aerosols could not grow large enough to spontaneously freeze in the time required."
In summary, there is no evidence that these "chemtrails" are other than expected, normal contrails from jet aircraft that vary in their shapes, duration, and general presentation based on prevailing weather conditionsBut to be able to persist for hours, the condition required is extreme and will be very rarely happen in reality.
If the atmospheric water content is not consistent with altitude (picture atmospheric "waves" of high water vapor content below a layer of low water vapor content much like waves on the ocean), then a jet will alternately pass through air that allows contrail formation and air that does not. This gives the appearance of a dashed line if the plane is flying at, or near the perpendicular to the waves.A possible explanation but not the only one. And may not be the real situation.
There were no pictures or evidence that indicated anything other than the above contrail formation phenomena.Scientist still can not explain why trails can last for hours too many times on an impossible situation.