plane(flying type) vapor trails

[shedbound]

O.k folks, calling on all you intellectual forumites to shed some light on the trails left by high altitude jets,
I am aware of the vapor trails, but I can't be the only one noticing what some refer to as "chemtrails"?
There seems to be some conspiracy theories around on the net, is it coincidence that these long white trails are left in parallel lines preceding hot weather?
As best as I can tell these are non commercial jets, the trails spread into a haze which really seems to intensify the sun's rays.
does anyone know anything about this? or should I just commit myself now?:?
Thanks in advance

[Bushmiller]

Shedbound

I don't think you could place me in the intellectual category so perhaps I shouldn't answer, but my understanding is that the exhaust gases from the gas turbines of a jet condense to form a vapour. It takes a few moments for them to cool sufficiently to become visible. This accounts for the gap between the engine and the visible vapour. It is also more noticeable as the aircraft flies higher and encounters cooler air.

Chemtrails? Not heard them called that.

Regards
Paul

[enelef]

I think the word is contrails
Contrail - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Contrail)
in short


Contrails (pron.: /'k?ntre?lz/; short for "condensation trails") or vapor trails are long thin artificial clouds that sometimes form behind aircraft. Their formation is most often triggered by the water vapour in the exhaust of aircraft engines, but can also be triggered by the changes in air pressure in wingtip vortices or in the air over the entire wing surface.[1] Like all clouds, contrails are made of water, in the form of a suspension of billions of liquid droplets or ice crystals.

Depending on the temperature and humidity at the altitude the contrail forms, they may be visible for only a few seconds or minutes, or may persist for hours and spread to be several miles wide. Persistent spreading contrails are thought to have a significant effect on global climate

Cheers

[shedbound]

Thanks for your replies, "chemtrails" is the conspiracy theorists term for "contrails".

[Bushmiller]

Persistent spreading contrails are thought to have a significant effect on global climate

Cheers

Now that is presumably the essence of the controversy!

Perhaps we are in the region of NOX and SOX which are the products of incomplete combustion and the precursors to acid rain under certsin circumstances. I suppose that would affect the climate a little.

I seem to recall that when all the aircraft were grounded in the US immediately after 911 there was a noticeable change in the climatic conditions or so it was alleged.

Regards
Paul

[BobL]

Is this what you mean?

249986249987

Photo taken by your truly at 9000 ft elevation with Canon 50D and 400 mm lens.

[Master Splinter]

Chemtrails are one of the enduring conspiracy theories on teh intarwebz. First observed by teh crazies in the mid 90's, they are a secret (government) plot to control the weather, spread mind control drugs, biological agents, psycotropics, or even seed the sky with electrically conductive material as part of a massive electronic superweapons testing program.

Wikipedia has a nice article on them, the TL;DR version is - water vapour is byproduct of combustion, when it cools down from the jet engine (typically taking a few seconds to chill to ambient temperature - which is below 0C at those heights) you see the ice crystals that have formed.

Chemtrails are about on par with the secret Nazi base established on the moon after WWII. (I can recommend watching Iron Sky, btw), or Sigmund Freud's thawing out (he was stored in the beer fridge at Area 51) to be used to attack the Taliban.

[enelef]

Shhh - you're not supposed to talk about those things. :doh:
That's why they're called secrets.

:roflmao2:

[Koala-Man]

This is from the IPCC's 4th assessment report published in 2007. Section 2.6 of the Scientific Basis Report you can find here.

Chapter 2: Changes in Atmospheric Constituents and in Radiative Forcing - AR4 WGI (http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch2.html)

"Aircraft produce persistent linear trails of condensation (‘contrails’) in regions that have suitably low temperatures and high humidity. Contrails are a form of cirrus cloud that refl ect solar radiation and absorb infrared radiation. Linear contrails from global aircraft operations have increased Earth’s cloudiness and are estimated to cause a small positive radiative forcing."

The effect doesn't seem to be very large. Section 2.6.4 also mentions aerosols from jets, but doesn't come to any firm conclusion.

[jimbur]

What can you expect when there are enough people signing a petition wanting the US Government to build a death star that they have to reply. At first it seems funny but then you realise that these people are serious and they base their science and history on the silver screen, the television and that repository of all wisdom, the internet.

[shedbound]

I'm ringing the asylum now.:U

[shedbound]

great shots BobL, that's exaclty what I was talking about.:2tsup:

[Sebastiaan56]

I signed that petition Jim, I thought it was a joke :rolleyes:

[vk4]

I thought that the Yanks had done that with their star wars program , I was of the opinion that they had placed a massive solar powered LASER platform in space in geosync orbit above the US of A.

You know how paranoid the YANKS are.

vk4

[RETIRED]

Chemtrails are one of the enduring conspiracy theories on teh intarwebz. First observed by teh crazies in the mid 90's, they are a secret (government) plot to control the weather, spread mind control drugs, biological agents, psycotropics, or even seed the sky with electrically conductive material as part of a massive electronic superweapons testing program.

Wikipedia has a nice article on them, the TL;DR version is - water vapour is byproduct of combustion, when it cools down from the jet engine (typically taking a few seconds to chill to ambient temperature - which is below 0C at those heights) you see the ice crystals that have formed.

Chemtrails are about on par with the secret Nazi base established on the moon after WWII. (I can recommend watching Iron Sky, btw), or Sigmund Freud's thawing out (he was stored in the beer fridge at Area 51) to be used to attack the Taliban.Good, at last I have a reason.:D

[Kev Y.]

Shedbound, I am planning on going flying over the weekend, I will make a point of buzzing your place :) look up and see if I leave any chemtrails :)

[NCArcher]

Interestingly, when the volcano in iceland errupted a while ago it spewed millions of tons (I may have exagerated that a bit, or not. I can't be bothered looking it up :p)(Edit:OK I looked it up) of CO2 into the atmosphere. The air/atmosphere was however cleaner than if the volcano hadn't errupted because of all the aircraft that were grounded for a period of time and weren't dumping man made CO2 into the atmosphere.
The grounding of European flights avoided about 344×106 kg of CO2 emissions per day, while the volcano emitted about 150×106 kg of CO2 per day.

[Bushmiller]

Thanks for your replies, "chemtrails" is the conspiracy theorists term for "contrails".

Firstly Shedbound thank you for introducing this subject, which I think is a very fitting alternative to wooden and steel planes :rolleyes:.

I remembered an issue which was dancing around in my head earlier (there's plenty of room) when you first raised this issue. It's Global Dimming.

In the early days the most ardent protagonists of global warming couldn't satisfactorily explain why the planet hadn't warmed quicker than it had, if what they were saying was true. Global Dimming is at least a partial reason why. Taken from Wikipedia:

"Some climate scientists have theorized that aircraft contrails (http://en.wikipedia.org/wiki/Contrail) (also called vapor trails) are implicated in global dimming, but the constant flow of air traffic previously meant that this could not be tested. The near-total shutdown of civil air traffic (http://en.wikipedia.org/wiki/Civil_aviation) during the three days following the September 11, 2001 attacks (http://en.wikipedia.org/wiki/September_11,_2001_attacks) afforded a unique opportunity in which to observe the climate of the United States (http://en.wikipedia.org/wiki/United_States) absent from the effect of contrails. During this period, an increase in diurnal (http://en.wikipedia.org/wiki/Day) temperature variation of over 1 °C (1.8 °F) was observed in some parts of the U.S., i.e. aircraft contrails may have been raising nighttime temperatures and/or lowering daytime temperatures by much more than previously thought."
A much fuller explanation can be seen here

Global dimming - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Global_dimming)

To save the less enthusiastic among you fifteen minutes reading, a whole heap of #### is being dumped on the upper surfaces of the clouds (also to a lesser extent on the undersides too, and it is reflecting heat that would otherwise have struck the earth back into space.

Simple really :cool: .

Regards
Paul

[shedbound]

very insightful replies thanks a million, I remember going to Boston(USA) as a young kid and have vague recollections of being told that the air traffic had to take off and land in a certain direction so as the emissions don't discolor the historical "white" buildings. If anyone can clarify this... And Kev.y I'd normally look for you but it's hard from my straight jacket in a lead lined room:wacko:(by the way must catch up soon)...
thanks again peoples
Joel

[Durdge39]

Chemtrails:
250941

(That's the high altitude variety for the Ag Boys) :D

[Bushmiller]

Durdge

That bloke's not trying. His wheels aren't even tickling the seed heads :rolleyes: .

Have you ever noticed that if they realise they are being watched the crop dusters become more daring again.

[damian]

Unfortunately I get cornered by the conspiracy set regularly. I make no comment on their "theories" but I do have a tip to stop them going on about it should you get cornered.

I first point out I've heard it all before, suggest it may be correct but then pose the question "what are you going to do about it" followed by the observation that worrying about things over which you have no control is pointless.

Usually stops them in their tracks because the starting point of most of these theories is that those prosecuting the scheme are secret powerful and unaccountable, thus effective action is virtually impossible.

We may well be ruled by a secret society of reptilian illuminate, but what's your plan to overthrow them ?

meh...