Saturday, 19 September 2009


These are produced by high flying aircraft. Their shape and form (and whether they form at all) depends on the atmospheric conditions at the time. The basic science of it is that the hot exhaust gasses mix with freezing air typically around -40 to -50C. The moisture generated turns into ice crystals which cause the thin linear clouds that we know as contrails. How long the trail is and how long it lasts depends on the air temperature and humidity. Interestingly they are now generally recognised as a cloud type, albeit manmade.

This picture was taken looking north west from our house. One can only guess as to the reason for the somewhat artistic manouevre undertaken by the aircraft on the right!


  1. Looks like it was avoiding the other one!

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  3. It does look a little like that doesn't it? I hope it is not though as it implies someone somewhere was not doing their job properly! All I can say is that the aircraft executing the turn was a Virgin Airbus A340. The other aircraft was a Ryanair Boeing 737.