Jet trails/exhaust.

dgacampbell · 06-07-16, 04:57 PM

https://en.wikipedia.org/wiki/Chemtr...spiracy_theory

sinbin5t · 06-07-16, 05:00 PM

Tin foil hat time

jimh · 06-07-16, 06:25 PM

Obviously you get patches of varying humidity up in the sky - if the patch is humid enough, it's a cloud, but I would imagine there is varying patches of humidity in "clear" sky.
I guess then that a jet can be flying in relatively humid sky, then hit a dry patch and the jet trails become apparent?
I guess this might vary over the UK partly due to the location each year of the jet stream, which I think is unusually positioned at the moment.

Or, maybe that's the source of the chemical "the man" uses to keep us all stupid, preventing us from noticing that "the man" is in fact a lizard!

Minty · 06-07-16, 07:09 PM

It could be to do with Brexit

dgacampbell · 06-07-16, 07:15 PM

Quote:

Originally Posted by Minty

It could be to do with Brexit

Hanuman · 06-07-16, 08:55 PM

We can fly at what appears to be a constant altitude, and the contrails can be sporadic. At other times, the contrail will be seamless.

The atmosphere is far from constant, but to gauge what conditions we actually have, there is a 'model' of the atmosphere, which assumes certain factors, such as-

Standard Sea level pressure. It's 1013mb. Which by odd chance is also my classic Audi membership number. 1013.
Standard Sea level temperature. 15°C
Standard Temperature and pressure changes with increase in altitude. 2°C loss per 1000ft increase, 30ft per millibar. Etc.
But only up to certain altitude, after which it follows a whole new set of rules.

Much of this is of very specific interest to us when driving our cars, too. Or rather, of interest to the engineers that designed our cars.

Cloud in the lower atmosphere is largely water vapour. Moisture in the atmosphere, which then benefits further from minuscule particles in the air, such as soot, to allow water droplets to form.
Cloud in the upper atmosphere tends towards being ice crystals.

In carburettors, in aircraft, carburettor icing is a major consideration, especially when operation in certain environments, such as around 10°C and below. But this is also a major issue in cars, too.

Likewise, the exhaust from cars carries a lot of water vapour, as a by product of combustion, and becomes less or more evident as ambient conditions change. As it does in aircraft.

There is little need to go seeking conspiracies when the atmosphere itself is quite capable of creating intriguing situations.

Hanuman · 06-07-16, 09:42 PM

In the aftermath of 911 (no more conspiracy theories...) with the large drop in air traffic, it was noted in many locations that atmospheric conditions had changed. Temperatures, cloud cover. There is no doubt that air travel does generate a lot of exhaust output.

moonwatcher · 07-07-16, 08:13 AM

Mother nature provides moisture in the atmosphere.
We send up a plane which sucks in massive amounts of the said atmosphere, mixes with the jet fuel inside the equivilent of your wall mounted condensing boiler and when the exhaust hits the cooler atmosphere it condenses and leaves a trail.
It's more obvious these days due to more efficient engines

sinbin5t · 07-07-16, 12:12 PM

Quote:

Originally Posted by jimh

Or, maybe that's the source of the chemical "the man" uses to keep us all stupid, preventing us from noticing that "the man" is in fact a lizard!

It's life jimh but not as we know it

06-07-16, 07:09 PM	#5
Minty Senior Member Classic Audi Club Member Join Date: Jul 2008 Location: Wirral Posts: 1,528	It could be to do with Brexit __________________ 1984 GT5E Topaz Green 1982 GT5S Helios Blue - now in Ireland 1983 GT5E Topaz Green - donor 1986 GT 2.0 Tornado Red - long gone 2001 A6 2.4 V6 - exported to Ireland

06-07-16, 08:55 PM	#7
Hanuman Trickster Classic Audi Club Member Join Date: May 2009 Location: Heckling from the cheap seats, Phnom Penh, KoW Posts: 7,016	We can fly at what appears to be a constant altitude, and the contrails can be sporadic. At other times, the contrail will be seamless. The atmosphere is far from constant, but to gauge what conditions we actually have, there is a 'model' of the atmosphere, which assumes certain factors, such as- Standard Sea level pressure. It's 1013mb. Which by odd chance is also my classic Audi membership number. 1013. Standard Sea level temperature. 15°C Standard Temperature and pressure changes with increase in altitude. 2°C loss per 1000ft increase, 30ft per millibar. Etc. But only up to certain altitude, after which it follows a whole new set of rules. Much of this is of very specific interest to us when driving our cars, too. Or rather, of interest to the engineers that designed our cars. Cloud in the lower atmosphere is largely water vapour. Moisture in the atmosphere, which then benefits further from minuscule particles in the air, such as soot, to allow water droplets to form. Cloud in the upper atmosphere tends towards being ice crystals. In carburettors, in aircraft, carburettor icing is a major consideration, especially when operation in certain environments, such as around 10°C and below. But this is also a major issue in cars, too. Likewise, the exhaust from cars carries a lot of water vapour, as a by product of combustion, and becomes less or more evident as ambient conditions change. As it does in aircraft. There is little need to go seeking conspiracies when the atmosphere itself is quite capable of creating intriguing situations. __________________ I wish they would keep the damned Chinese away now that I can go home, so that I can enjoy Fish amok and a draught Angkor Last edited by Hanuman; 06-07-16 at 09:38 PM.

06-07-16, 09:42 PM	#8
Hanuman Trickster Classic Audi Club Member Join Date: May 2009 Location: Heckling from the cheap seats, Phnom Penh, KoW Posts: 7,016	In the aftermath of 911 (no more conspiracy theories...) with the large drop in air traffic, it was noted in many locations that atmospheric conditions had changed. Temperatures, cloud cover. There is no doubt that air travel does generate a lot of exhaust output. __________________ I wish they would keep the damned Chinese away now that I can go home, so that I can enjoy Fish amok and a draught Angkor

07-07-16, 08:13 AM	#9
moonwatcher 4 ring whore! Classic Audi Club Member Join Date: Jul 2008 Location: Barrow in Furness, Cumbria Posts: 2,049	Mother nature provides moisture in the atmosphere. We send up a plane which sucks in massive amounts of the said atmosphere, mixes with the jet fuel inside the equivilent of your wall mounted condensing boiler and when the exhaust hits the cooler atmosphere it condenses and leaves a trail. It's more obvious these days due to more efficient engines __________________ Coupe Quattro 1985

06-07-16, 04:57 PM	#2
dgacampbell Senior Member Classic Audi Club Member Join Date: May 2011 Location: Co.Armagh, N.Ireland Posts: 1,442	https://en.wikipedia.org/wiki/Chemtr...spiracy_theory

06-07-16, 05:00 PM	#3
sinbin5t 4 ring whore! Classic Audi Club Member Join Date: Jan 2010 Location: Where a spike points skywards Posts: 12,960	Tin foil hat time

06-07-16, 06:25 PM	#4
jimh Grown up member Classic Audi Club Member Join Date: Dec 2008 Posts: 122	Obviously you get patches of varying humidity up in the sky - if the patch is humid enough, it's a cloud, but I would imagine there is varying patches of humidity in "clear" sky. I guess then that a jet can be flying in relatively humid sky, then hit a dry patch and the jet trails become apparent? I guess this might vary over the UK partly due to the location each year of the jet stream, which I think is unusually positioned at the moment. Or, maybe that's the source of the chemical "the man" uses to keep us all stupid, preventing us from noticing that "the man" is in fact a lizard!