Comments on: Aerodynamic and Rainbow Contrails

By: Uncinus

Uncinus — Fri, 12 Feb 2010 22:56:41 +0000

But it’s not a rainbow. Did you read the explanation?

http://contrailscience.com/files/Gierens_Aerodynamic_poster_060625.pdf

By: danjferg

danjferg — Fri, 12 Feb 2010 22:48:28 +0000

The presence or absence of the rainbow colors in the contrail is a result of the angle formed between the viewer, plane and the incident light. The presence of a rainbow is dictated by the way light refracts off of circular water droplets. Most sky rainbows are seen when the sun is low and at your back. In the images above I’d guess that the sun had to be very low in the sky to see a rainbow from directly below the aircraft. Someone call the photographer and very for me?

If you can handle a little physics check out the MIT lecture at http://video.google.com/videoplay?docid=-2978729867097229598&ei=Ddl1S83zH5PorAKF9PjdBw&q=mit+rainbows&hl=en&view=3#

By: JazzRoc

JazzRoc — Fri, 15 Jan 2010 23:24:58 +0000

Andy: in far infrared light the contrails may well be much larger than they look to us
I’m not sure about that. They are mostly made of ice frozen much colder than freezing point. There will be a touch of supercooled water too. If there’s no ice there, there will be no trail there either

The heat collected may well melt the ice crystals
They must remain in the same state at that altitude in that stratospheric layer. Any temperature rise will instantly accelerate (and warm) the next impinging air molecules.

the heated droplets could re-radiate the heat out in all directions.. some of which returns to earth enhancing global warming
They won’t be droplets. The ice crystals will reflect back infra-red downwards, “blanketing” the Earth during darkness. But they also reflect back sunlight (raising the albedo) during daylight. The net result is moot.

The epa report on contrails shows the visible contrail cover in some areas is 2-3%. I think its unlikely we can change anything about the planet by this much and then expect no repercussions
That is 2-3% where there actually IS a contrail. It is not 2-3% of the Earth’s surface as a whole. You must remember the surface area of the US amounts to only 2% of the surface area of the Earth.

Tell you what – why don’t you read the “Contrails-to-Cirrus” link above left on this page and see whether you agree or not? It seems to be well covered there…

By: andy

andy — Fri, 15 Jan 2010 21:25:15 +0000

If you examine the absorption spectra of water you will find it takes about 10m of water to stop visible light (i.e. sunlight) but only 10 millionths of a meter to stop far infrared (i.e. heat radiated from the earth) – Thats why water appears clear to our eyes but water containing samples need to be made very thin for IR spectrometry.

So in far infrared light the contrails may well be much larger than they look to us.

The heat collected may well melt the ice crystals and then the heated droplets could re-radiate the heat out in all directions.. some of which returns to earth enhancing global warming.

The epa report on contrails shows the visible contrail cover in some areas is 2-3%. I think its unlikely we can change anything about the planet by this much and then expect no reprecussions.

By: Shilltastic

Shilltastic — Wed, 11 Nov 2009 16:46:58 +0000

TrutherD, of course your comment will remain! It’s precisely the type of ignorance that those of us who understand the facts like to see! With that comment, you have just said “I know nothing about the atmosphere or aviation and I also accept youtube videos, made by OTHER ignorant people as “fact”, simply because I’m too lazy to research this from the perspective of peer reviewed scientific fact”. Thanks! That video is nothing but paranoid trash made by someone else who is clueless about the truth.

By: TrutherD

TrutherD — Wed, 11 Nov 2009 13:50:08 +0000

Chemtrails appear at all altitudes and all temperatures and humidity levels. At 26,000ft+ in temperatures of -40C where contrail formation is optimal they last about a minute. Watch the documentary “Don’t talk about the weather”, then decide. It’s on YouTube. Features hundreds of chemtrail vs. contrail videos comparing the two in the same sky and also chemtrails starting and stopping, laid in patterns like parallel lines and grids, shapes likes Xs, As and Zs. I highly doubt this comment will remain live.

By: Wayne Farley

Wayne Farley — Mon, 21 Sep 2009 00:50:25 +0000

I am perpetually intrigued by aviation and aerospace operations. Very interesting collection of contrails images….these are works of art.

By: Anonymous

Anonymous — Thu, 27 Aug 2009 00:53:19 +0000

[...] [...]

By: Ross

Ross — Sun, 17 May 2009 05:54:20 +0000

But without freezing temperatures to convert the water vapor to ice crystals, they also disappear in a fraction of a second.

… unless the RH is high enough that the air is ice-supersaturated.

By: The Stig

The Stig — Sat, 16 May 2009 21:51:07 +0000

You don’t need planes to see an aerodynamic contrail. Just look at a Formula1 car when it’s driving at 200mph through humid weather at the Brazilian Grand Prix, or any of the numerous hot and humid races they run. As the “wings” at the front and back create downforce, they deflect the air at a sharp angle and condense the moisture from the air. But without freezing temperatures to convert the water vapor to ice crystals, they also disappear in a fraction of a second.