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
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?

Jetstreams2.jpgJetstreams3.jpg

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.
That's why they're called secrets.

[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

"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.

[shedbound]

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

[Sebastiaan56]

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

[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.