Contrail
Shadow by Ágúst
Guðmundsson.
Imaged during the 10th Paragliding World Championship 500 km north
of Sydney, Australia March 4,'07.
©�g�st Gu�mundsson, shown with permission.
Aircraft contrails are occasionally seen paired
with a dark
line, their shadow cast onto on a lower
layer of very thin
cirrus cloud or atmospheric haze.
Here the shadow is cast deep through the hazy atmosphere. The shadow
is a 3D volume of unlit air that
extends down to ground level.
The shadow might also be cast onto the landscape. Alternatively, the
distant hills could appear darker because the intervening shadowed
air cannot scatter (predominantly blue) sunlight.
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