Aircraft contrail
{"Image ImageDescription": "^BAircraft contrail.^b Airplane producing a contrail, or vapour trail in a partially cloudy sky. Contrails are artificial clouds formed from frozen water droplets from the exhaust of the engines of an aircraft. They form when aircraft are flying at altitudes exceeding 5000 metres and when the upper atmosphere is nearly saturated with moisture. In dry air the contrail quickly dissipates. Photographed over Finland.", "Image XResolution": "72", "Image YResolution": "72", "Image ResolutionUnit": "Pixels/Inch", "Image YCbCrPositioning": "Centered", "Image Copyright": "Science Photo Library"}