Vapour Trails
Từ Future Of Mankind
Water vapour that looks like a line of white smoke behind an aeroplane as it flies. The main products of hydrocarbon fuel combustion are carbon dioxide and water vapour. At high altitudes this water vapour emerges into a cold environment, and the local increase in water vapour can raise the relative humidity of the air past saturation point. Condensation is the reverse of vapourisation.
