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Strange Black Line over NYC

Posted: Mon Feb 23, 2009 2:44 am
by magic1whiz
I was on the Staten Island Ferry on 2/21/09 en route back to New York City (leaving Staten Island). I maneuvered to the lowest deck on the front (closest to the water). I then noticed this strange black line that ran almost parallel to a contrail except this line was perfectly straight (which suggests to me there is something optical going on here and it isn't smog or anything). It was exactly 4:33 pm EST when this picture was snapped and I was facing roughly NE at the time. As the ferry progressed the line completely disappeared. Any ideas what the heck this thing might be?
unkown_black_line.jpg
unkown_black_line.jpg (59.02 KiB) Viewed 482 times

Re: Strange Black Line over NYC

Posted: Mon Feb 23, 2009 5:30 am
by BMAONE23
I've noticed this myself on several occations. What you are seeing is the Shadow created by the Contrail. It only happens when the relative angle of the sun the trail and your perspective line up. The Sun was likely up and to the left at the time the image was taken. Although the trails seem to get stretched and distorted over a relatively small ammount of time, their shadows still appear to be straight.

Re: Strange Black Line over NYC

Posted: Mon Feb 23, 2009 4:41 pm
by neufer
BMAONE23 wrote:I've noticed this myself on several occasions. What you are seeing is the Shadow created by the Contrail. It only happens when the relative angle of the sun the trail and your perspective line up. The Sun was likely up and to the left at the time the image was taken. Although the trails seem to get stretched and distorted over a relatively small amount of time, their shadows still appear to be straight.
The sun is clearly up & to the left (based on the lighting on the buildings & the other ferry boat). If "magic" had looked back at the sun at the time he might have seen that the left contrail actually crossed through the sun. It is that short straight cirrus piece cutting through the sun (as seen by the observer) that is leaving a flat shadow plane in the smog haze in the vicinity of the observer (and not the more distant long squiggly cirrus line which parallels the nearby shadow).