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i need old images of persitent vapor trails.....

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posted on Jul, 23 2009 @ 09:38 AM
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here is what nasa has to say about it. this is from a pbs nova special.



A lingering concern If conditions are right, newly formed contrails will begin feeding off surrounding water vapor. Like vaporous cancers, they start growing and spreading. In time, they can expand horizontally to such an extent that they become indistinguishable from cirrus clouds, those thin, diaphanous sheets often seen way up high. These artificial cirrus clouds can last for many hours, and the amount of sky they end up covering can be astonishing: one study showed that contrails from just six aircraft expanded to shroud some 7,700 square miles.


nava, dimming the sun




Persistent (non-spreading) contrails look like long white lines that remain visible after the airplane has disappeared. This shows that the air where the airplane is flying is quite humid, and there is a large amount of water vapor available to form a contrail. Persistent contrails can be further divided into two classes: those that spread and those that don't. Persistent contrails look like long, narrow white pencil-lines across the sky. Persistent spreading contrails look like long, broad, fuzzy white lines. This is the type most likely to affect climate because they cover a larger area and last longer than short-lived or persistent contrails.



nasa site


i raised this question numorous times in another thread. the closest we got to an answer was a ww2 video that did not show anything behind the planes as far as persistence.
personally all i really know about the vapor/chem trail issue is what i see with my own eyes, and what people like the cfr, un etc....admit to in documents, although they make it sound like it's only in the planning stage i do believe there is operations in progress.
my inquiry involvers these persistent vapor trails, i think they only began in the mid-90's, or possibly a bit earlier. i cannot find old fotos or images showing these contrails.
this tells me 2 things, either the atmosphere changed so much in the last 20 years or so that persistent contrails are a new phenomenon, or,
chemtrails are real, and the term persistent contrails is just a coverup term being used.




posted on Jul, 23 2009 @ 10:05 AM
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There are quite some photos from WW2 showing the contrails of true airplane fights; images.google.com... .

I've to admit it surprised me to see how many persistent contrails of older days have been captured on film - I was under the impression that the contrails-cirrus clouds are mainly created by the huge amount of contrail vapors, not as much the contrails themselves. Seeing as the human population has never flown as much as today, that would make sense.. But oh well


[edit on 23-7-2009 by scraze]



posted on Jul, 23 2009 @ 10:33 AM
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reply to post by scraze
 


WW2 prop planes spewing diesel fuel exhaust is not the same as the persistent contrails you see today. Can anyone post a picture from the 70's or 80's showing persistent contrails from modern jets forming a grid pattern in the sky and expanding into a hazy cloud cover? I have yet to see one prior to 1995.



posted on Jul, 23 2009 @ 10:34 AM
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reply to post by rubbertramp
 




This is a composite of a series of jet flights over the CONUS. Not every flight makes a contrail, of course. BUT it shows quite clearly why there are so many contrails.

In your OP it describes why some persist so long. Not sure how still photos are going to help, what you really need are time-lapse.



How Long do Contrails Last?

Q) How long do contrails last?
A) Anywhere from less than a second, up to several hours.


This is an oft-asked question. The answer is reasonably straightforward, but misunderstanding is common. To understand why a contrail can last as little as a fraction of a second, or as long as several hours, you need to understand what a contrail is, and how it forms.

Here’s another question, which has the same answer:

Q) How long does a snowflake last?

Why is this basically the same question? Because contrails are generally made of ice crystals. Jet exhaust contains a lot of water vapor (the chemical reaction actually produces more water than there was originally jet fuel), and when this gets shot out of the back of the engine at 2000MPH, it hits the frigid air (typically colder than -40 degrees), and the water vapor condenses and freezes, very quickly, into tiny ice crystals, just like snowflakes.

So why do these ice crystals sometimes stay around for a long time, and sometimes vanish in seconds? The temperature is well below freezing, so they can’t melt, can they? This is puzzling, because it involves something that most people know nothing about: “sublimation“.

Sublimation is when a substance (in this case, water), goes directly from being solid to being vapor (a gas), without actually melting into a liquid. It’s like evaporation, except instead of a liquid evaporating, it’s a solid (ice). If the air is dry (i.e. there is little water vapor in it), then the ice crystals will quickly sublimate into vapor, and the trail will vanish quickly.

However, if the air already has a lot of water vapor in it, then the ice will sublimate slower, and the trail will last longer.

If the air has so much water vapor in it already that it can’t hold any more (i.e. it’s “supersaturated”), then the ice crystals can’t sublimate, and so the contrail will stay around for a long time. The ice crystals might even attract water from the air, if there is enough, and the contrail will get thicker. Winds might make the contrail spread out to even cover the whole sky.

The above is a simplification, as other factors like temperature, pressure, and sunlight have an effect. But it explains the basic reasons why some trails last only a few seconds, and some can last for hours, and spread out to cover the sky.

Finally, there is one more way of asking the question:

Q) How long do clouds last?

This is the same question because contrails are clouds. Contrails are physically very similar to cirrus clouds (except they are long and thin), and so they act almost exactly the same. You see cirrus clouds that last for hours, so why not contrails?


contrailscience.com...


[edit on 23 July 2009 by weedwhacker]



posted on Jul, 23 2009 @ 10:41 AM
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reply to post by weedwhacker
 


sorry, i did not mean this.




i cannot find old fotos or images showing these contrails.


i meant fotos or video/film.

thanx for pointing that out.

[edit on 23-7-2009 by rubbertramp]



posted on Jul, 23 2009 @ 10:43 AM
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one thing i always wondered about the science of this.
on a cold damp morn, when your breath causes vapor, why under no condition does it persist, linger, and turn into a small cirrus cloud?



posted on Jul, 23 2009 @ 10:43 AM
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reply to post by Erasurehead
 


Erasurehead,

Here is a short video with news reports from 1969 about the phenomenom:




posted on Jul, 23 2009 @ 10:46 AM
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reply to post by rubbertramp
 



...when your breath causes vapor, why under no condition does it persist, linger, and turn into a small cirrus cloud?


Not the same thing. Cirrus form of ICE crystals, in temperatures of well below -20 degrees C. IF you were in an enviroment that cold, and could breathe out vast amounts of moisture (not just the few quarts from your lungs) then you'd make clouds.



posted on Jul, 23 2009 @ 10:52 AM
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reply to post by rubbertramp
 


You should watch old movies, mainly westerns where there are numerous open sky shots. Not a "contrail" in sight. Even newer movies and some commercials will inadvertently forget to blot out a chemtrail. Some commercials that show outdoor scenes have CGI skies! Funny.

I grew up on AF Bases with planes flying in and out all the time, never seen a contrail last more than a minute. But now. We have to be convinced that our own eyes are deceiving us. That what we remember is not what we remember, etc.



posted on Jul, 23 2009 @ 11:09 AM
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reply to post by Hazelnut
 



I grew up on AF Bases with planes flying in and out all the time, never seen a contrail last more than a minute.


Hazel, if you wer living ON the base, then the airplanes you saw were taking off and landing, right? They don't form contrails during those times.

Let me guess...sometimes you saw a trail of vapor behind an airplane taking off or landing, on a very humid day?

Here's a YT video someone posted, he thinks it's fuel being dumped --- it isn't. It is condensation trail coming off the flap, in the very humid air near Myrtle Beach.



posted on Jul, 23 2009 @ 11:16 AM
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reply to post by weedwhacker
 


I don't know what the video was supposed to show me but it sounded accurate. We lived on bases in California, North Dakota, Ohio, Taiwan and Japan. Some places were humid, some were not.

What I see these days is nothing like the good old days. I have a video I made with my camcorder last year. But its got a teeny little disk that my PC wont recognize so I can't upload it




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