The video was captured using an iPhone
camera. It shows a view of the ground taken through the window of
a Delta Airlines flight from Phoenix to Atlanta at 1300 hrs Phoenix
time on 12 Jan 2010. The sky was clear.
In the video, you can see a bright circle moving over the ground
followed by a dark line. The dark line is, I believe, the shadow
of the contrail presumably being generated by the aircraft.
The bright circle is what I find puzzling. As it moved across the
ground, it brightened dirt, trees, etc. Vehicles that were within
the bright circle glowed brightly red or blue or green (whatever color
they were painted presumably). They seemed to fluoresce.
The camera I used did not pick this up. Snow fields did not seem
to brighten noticably.
The bright spot was just in front of the contrail shadow and apparently
coincident with a straight line from the sun through the aircraft to
the ground, i.e., the sun, the aircraft, and the bright circle lie on a
straight line.
So my question is what is the cause of the bright circle?
- A diffraction effect caused by air being compressed by the
aircraft? Sort of a lens effect?
- Normal specular reflection? (Why would the light appear to
be focused?)
- Something else?
I am dissatisfied with any hypothesis I have been able to come up
with.
Please help.
Explain why this bright circle exists and the explain physics of this
phenomenon.
