The sky over a corner of Hampshire on a particularly still day, September 2012.
Skygeometry
A wild slim alien
The sky over a corner of Hampshire on a particularly still day, September 2012.
A wild slim alien 
September 24, 2012 at 4:58 pm
This is pretty bonkers. No upper-level winds, I guess.
September 24, 2012 at 5:26 pm
And it’s not like it feels that we get that many planes overhead, either – some of those vapour trails must have been hanging more or less motionless for quite some time.