What is this swirly contrail I photographed?

Good Morning to all.
For your consideration,

I photographed these is Upstate New York whilst driving west on Route 17 near Bloomingburg.
it was a persistent contrail with a faint black line behind it, which also did not fade.
I observed it for over a minute while i drove by that stretch of highway.

What say ye?
stunt pilot?
Chemtrail Barrel Roll Maneuver?
Aliens?
Haarp?
Wind?

a reply to: dashen

Winds. I've seen other contrails do that after watching the plane fly over perfectly normally.

a reply to: Zaphod58

and the black line?

a reply to: dashen

It's a contrail shadow. There's a very thin layer of cloud that you can't see with the naked eye under the contrail, and that's the shadow of the contrail that you see.

a reply to: Zaphod58

Very good then.
Wind it is.
Much thanks.

originally posted by: dashen
a reply to: Zaphod58

Very good then.
Wind it is.
Much thanks.

a reply to: MagicWand67

Yes, it is.

You haven't offered anything else.

a reply to: Zaphod58

I been thinking about what you said about the contrail shadow.
if thats the case then why is the black like perfectly straight all the way to the horizon and extends all the way INTO the helix contrail?

originally posted by: dashen
a reply to: Zaphod58

I been thinking about what you said about the contrail shadow.
if thats the case then why is the black like perfectly straight all the way to the horizon and extends all the way INTO the helix contrail?

It's an edge shadow.

a reply to: Bedlam

i mean a shadow of what?
the white cloudy part is all blown around and disappearing but the black line is ruler straight and actually enters the white of the contrail. what is straight that is casting the shadow?

originally posted by: dashen
a reply to: Bedlam

i mean a shadow of what?
the white cloudy part is all blown around and disappearing but the black line is ruler straight and actually enters the white of the contrail. what is straight that is casting the shadow?

It's a shadow of the contrail. The part that's casting the shadow is casting a sort of fan-shaped shadow on the clouds below. That type of shadow is always straight and goes to the horizon.

If you could see the sun in the photo, the contrail would be lined up with the sun to cause it.

a reply to: Bedlam

are we talking about the same faint black line. which is both thinner, a different shape, and extends into the helix of the contrail. none of which are fan shaped?
that line?

originally posted by: dashen
a reply to: Bedlam

are we talking about the same faint black line. which is both thinner, a different shape, and extends into the helix of the contrail. none of which are fan shaped?
that line?

You have to think of it in 3D. If I could draw it out on a white board it would be easier to explain.

Google "volumetric shadow" or "edge shadow". There are a few references to it.

Think of it this way. You have a desk lamp somewhat overhead, shining on your desk. If you stick your hand into the light between the lamp and the desk, with your palm flat to the desk, you will cast a hand shaped shadow.

However, if you turn your hand on edge, with the hand aligned so that it's edge on to the lamp, you'll cast a fan shaped shadow in space, the projection of which on the desk will be a line. Despite you having fingers. If I were a jelly bean sized resident of the desk top, and off at an angle, I could see your fingers, yet there would be a black line on the ground, and I might say, why is that branchy thing in the sky casting a black line on the deskland? Why do I not see branchy finger shadows on the ground?

Another example...

a reply to: Bedlam

then yes. yes we were talking about the same line. it was a result of the leading edge casting a shadow.
Case closed.
unless aliens.....

originally posted by: dashen
a reply to: Bedlam

then yes. yes we were talking about the same line. it was a result of the leading edge casting a shadow.
Case closed.
unless aliens.....

There's an even better photo that I used to see around a lot. Still looking.

Got it!



The detailed explanation...

a reply to: Bedlam

well. i for one learned a few things about a few things in this thread.
much thanks Bedlam

originally posted by: dashen
a reply to: Bedlam

well. i for one learned a few things about a few things in this thread.
much thanks Bedlam

i have quadrupled my knowledge of aviation and meteorology from these guys posts...you should read through the pages in this subforum..very interesting

a reply to: dashen

then yes. yes we were talking about the same line. it was a result of the leading edge casting a shadow.

Here is a good explanation for them...

www.atoptics.co.uk...

I was about to post a similar picture asking the same question. Thanks everyone