# More questions regarding chemtrails **URL:** \ **Category:** Cecil's Columns/Staff Reports\ **Created:** [May 2, 2011, 2:55am UTC](https://boards.straightdope.com/t/more-questions-regarding-chemtrails/580440 "2011-05-02T02:55:52Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![monesmartgirl](https://avatars.discourse-cdn.com/v4/letter/m/ad7895/32.png) [@monesmartgirl](https://boards.straightdope.com/u/monesmartgirl)\ **Post date:** [May 2, 2011, 2:55am UTC](https://boards.straightdope.com/t/more-questions-regarding-chemtrails/580440/1 "2011-05-02T02:55:52Z")
Why are there hundreds of chemtrails criss-crossing the sky one day, but not the next? Why do chemtrails start at a cities edge and cut off after the jets clear the other side? I’ve seen a chemtrail jet leave a trail across the city, cut the spray off, make a visible u-turn, turn the spray back on and leave another trail as it flew back over the city in the direction it came from. Why would this be done? ---
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [May 2, 2011, 3:07am UTC](https://boards.straightdope.com/t/more-questions-regarding-chemtrails/580440/2 "2011-05-02T03:07:46Z")
Welcome to the Straight Dope **monesmartgirl** It is customary to link to the column so everyone know what we are discussing. Here is the [column](http://www.straightdope.com/columns/read/2556/are-jet-contrails-the-latest-threat). ---
**Author:** ![TSBG](https://avatars.discourse-cdn.com/v4/letter/t/77aa72/32.png) [@TSBG](https://boards.straightdope.com/u/TSBG)\ **Post date:** [May 2, 2011, 4:56am UTC](https://boards.straightdope.com/t/more-questions-regarding-chemtrails/580440/3 "2011-05-02T04:56:50Z")
I wonder what the latest on contrails is–not the chemtrail nonsense, but in the context of climate change. I know I’ve read that while planes were grounded after 9/11 in the US that the temperature was warmer that usual; I wonder if there were any effects in Europe due to grounding of planes during the Icelandic volcano, or if the dust clouds were the dominant factor in the weather at the time. Speculating wildly, could lots of jets flying around help mitigate global warming in the short term? Does anyone know anything more recent about contrails and climate? Finally, could there be be such a thing as a chemtrail that kills only conspiracy theorists, and wouldn’t that be a good thing? ---
**Author:** ![Sailboat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sailboat/32/461_2.png) [@Sailboat](https://boards.straightdope.com/u/Sailboat)\ **Post date:** [May 4, 2011, 12:43pm UTC](https://boards.straightdope.com/t/more-questions-regarding-chemtrails/580440/4 "2011-05-04T12:43:15Z")
> [@fgasparini](#): > > I wonder what the latest on contrails is–not the chemtrail nonsense, but in the context of climate change. I know I’ve read that while planes were grounded after 9/11 in the US that the temperature was warmer that usual My recollection of the three days after 9/11 is not that it was “warmer” than usual, but that scientists were quoted in the paper as noting that there was much less cloud cover and little rain. Scientists speculated that the link between contrails and cloud cover may be stronger than we thought. I could be wrong, but that seems to jibe with this part of Cecil’s article: > [@](#): > > In research published in 1998, NASA scientists found that by circling a jet off the Pacific coast they were able to create contrails that eventually coalesced into a cirrus cloud covering 1,400 square miles. An examination of satellite photographs turned up an instance of jet contrails produced by commercial aircraft over New Mexico forming a cloud covering 13,000 square miles. NASA atmospheric scientist Patrick Minnis thinks the publicity surrounding these revelations may have been what set off the chemtrail nuts. Cirrus cloud cover is thought to have increased significantly over the U.S. since 1971, possibly due to jet travel. ---
**Author:** ![EvilTOJ](https://avatars.discourse-cdn.com/v4/letter/e/ee59a6/32.png) [@EvilTOJ](https://boards.straightdope.com/u/EvilTOJ)\ **Post date:** [May 4, 2011, 1:55pm UTC](https://boards.straightdope.com/t/more-questions-regarding-chemtrails/580440/5 "2011-05-04T13:55:21Z")
> [@monesmartgirl](#): > > Why are there hundreds of chemtrails criss-crossing the sky one day, but not the next? Why do chemtrails start at a cities edge and cut off after the jets clear the other side? I’ve seen a chemtrail jet leave a trail across the city, cut the spray off, make a visible u-turn, turn the spray back on and leave another trail as it flew back over the city in the direction it came from. Why would this be done? The behavior you describe doesn’t happen. Planes don’t cross back and forth over cities, but they do avoid each other in high traffic areas. So you’ll get multiple contrails all going the same way because … wait for it… the planes are avoiding each other. Also, you never see more than one contrail over a secluded area because air traffic only concentrates where the airports are. Airports, naturally, are near cities. ---
**Author:** ![b2220128](https://avatars.discourse-cdn.com/v4/letter/b/838e76/32.png) [@b2220128](https://boards.straightdope.com/u/b2220128)\ **Post date:** [May 5, 2011, 4:56pm UTC](https://boards.straightdope.com/t/more-questions-regarding-chemtrails/580440/6 "2011-05-05T16:56:03Z")
> [@monesmartgirl](#): > > Why are there hundreds of chemtrails criss-crossing the sky one day, but not the next? Why do chemtrails start at a cities edge and cut off after the jets clear the other side? I’ve seen a chemtrail jet leave a trail across the city, cut the spray off, make a visible u-turn, turn the spray back on and leave another trail as it flew back over the city in the direction it came from. Why would this be done? Your assuming that chemtrials exist then trying to determine how and why of an assumed phenomenon puts the cart before the horse. First show that they do in fact exist then worry about who, what, where and why. ---
**Author:** ![bump](https://avatars.discourse-cdn.com/v4/letter/b/7c8e57/32.png) [@bump](https://boards.straightdope.com/u/bump)\ **Post date:** [May 5, 2011, 6:06pm UTC](https://boards.straightdope.com/t/more-questions-regarding-chemtrails/580440/7 "2011-05-05T18:06:21Z")
> [@monesmartgirl](#): > > Why are there hundreds of chemtrails criss-crossing the sky one day, but not the next? Why do chemtrails start at a cities edge and cut off after the jets clear the other side? I’ve seen a chemtrail jet leave a trail across the city, cut the spray off, make a visible u-turn, turn the spray back on and leave another trail as it flew back over the city in the direction it came from. Why would this be done? First, they’re contrails (short for “condensation trails”) which are formed when the water vapor in jet turbine exhaust condenses and freezes, forming a visible cloud-type thing behind the plane. Second, they don’t begin/end when the jets go over a city; I’ve seen high flying jets leaving contrails straight across Dallas, Houston and Austin plenty of times. What you may see is that there may be more outside of major cities, simply because outside of major cities, the planes are at altitude, while close in, they’re on approach for landing, or climbing after takeoff, and are below the minimum altitude for contrail formation. You may have seen a skywriter or something else when it did the u-turn, or I suppose (although it’s really unlikely) some sort of engine failure and restart. ---
**Author:** ![Jackmannii](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jackmannii/32/311_2.png) [@Jackmannii](https://boards.straightdope.com/u/Jackmannii)\ **Post date:** [May 6, 2011, 12:53am UTC](https://boards.straightdope.com/t/more-questions-regarding-chemtrails/580440/8 "2011-05-06T00:53:18Z")
The evil folks who are unleashing “chemtrails” all over the U.S. have loved ones, friends and relatives who’d be exposed to whatever agents are allegedly being “sprayed” from jets for nefarious purposes - not to mention their own exposures. How are all these people supposedly being protected from Government Spray Juice? Seeing someone wearing a gas mask to the Safeway would be a dead giveaway but that hardly ever happens, even when there’s a cleanup on a pickle spill in aisle 10. ---
**Author:** ![Sailboat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sailboat/32/461_2.png) [@Sailboat](https://boards.straightdope.com/u/Sailboat)\ **Post date:** [May 6, 2011, 3:24pm UTC](https://boards.straightdope.com/t/more-questions-regarding-chemtrails/580440/9 "2011-05-06T15:24:52Z")
> [@Jackmannii](#): > > The evil folks who are unleashing “chemtrails” all over the U.S. have loved ones, friends and relatives who’d be exposed to whatever agents are allegedly being “sprayed” from jets for nefarious purposes - not to mention their own exposures. Look, I’m as sure as you are that “chemtrails” are conspiracy-theory nonsense, but this is a pretty poor argument for debunking it. There are plenty of cases of both [private individuals](http://en.wikipedia.org/wiki/Times_Beach,_Missouri), [corporations](http://en.wikipedia.org/wiki/Minimata_Disease), and [governments](http://en.wikipedia.org/wiki/Downwinders) releasing deadly contaminants into populated areas that wound up causing serious health effects. I know it _sounds_ illogical, but it happens. “Chemtrails” isn’t happening, but it’s not because people always show good judgment about poisoning their loved ones and/or neighbors. ---
**Author:** ![Irishman](https://avatars.discourse-cdn.com/v4/letter/i/b487fb/32.png) [@Irishman](https://boards.straightdope.com/u/Irishman)\ **Post date:** [May 6, 2011, 7:03pm UTC](https://boards.straightdope.com/t/more-questions-regarding-chemtrails/580440/11 "2011-05-06T19:03:39Z")
> [@bump](#): > > Second, they don’t begin/end when the jets go over a city; I’ve seen high flying jets leaving contrails straight across Dallas, Houston and Austin plenty of times. I think you have her comment backwards. She is accusing them of turning the chemtrails on over the cities and turning them off at the edges of cities, not spraying down the hinterland and leaving the cities free of poison. And since she hasn’t returned, I would like to point out the irony inherent in her username: “[I’]m one smart girl” . If you’re so smart, where’d the “I” go? ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [May 6, 2011, 7:54pm UTC](https://boards.straightdope.com/t/more-questions-regarding-chemtrails/580440/12 "2011-05-06T19:54:05Z")
**Sailboat** , those are completely different from what people are claiming about so-called chemtrails. All of those are cases of _negligent_ exposure: It’s not that anyone was deliberately poisoning people; they just didn’t care (or care enough). What we’re talking about here, though, would be (if it were true) _deliberate_ exposure. As for the OP’s purported u-turn, probably what she actually saw was one plane going one way leaving the atmospheric conditions that cause contrails, and another completely separate plane going the other way entering those conditions. Planes themselves are very hard to spot at those heights, and it’d be easy to lose sight of one long enough to get confused that way. ---
**Author:** ![Qwisp](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/qwisp/32/397_2.png) [@Qwisp](https://boards.straightdope.com/u/Qwisp)\ **Post date:** [May 6, 2011, 9:06pm UTC](https://boards.straightdope.com/t/more-questions-regarding-chemtrails/580440/13 "2011-05-06T21:06:21Z")
Contrails occur due to the temperature at plane level. Whether or not depends on how warm it is. The temperture above a city could be warmer due to the fact that cities have a lot more asphalt and concrete. Planes also sometimes have to circle a city before being allowed to land due to runway space and such. ---
**Author:** ![Jackmannii](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jackmannii/32/311_2.png) [@Jackmannii](https://boards.straightdope.com/u/Jackmannii)\ **Post date:** [May 6, 2011, 9:14pm UTC](https://boards.straightdope.com/t/more-questions-regarding-chemtrails/580440/14 "2011-05-06T21:14:17Z")
> [@Irishman](#): > > And since she hasn’t returned, I would like to point out the irony inherent in her username: “[I’]m one smart girl” . If you’re so smart, where’d the “I” go? There is no “I” in “mone”. Needless to say, there is no convincing chemtrail enthusiasts with facts and logic, any more than that’ll work with all the other conspiracies such folk typically believe (in accordance with the principle of crank magnetism). ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [May 6, 2011, 10:01pm UTC](https://boards.straightdope.com/t/more-questions-regarding-chemtrails/580440/15 "2011-05-06T22:01:33Z")
> [@bump](#): > > You may have seen a skywriter or something else when it did the u-turn, or I suppose (although it’s really unlikely) some sort of engine failure and restart. Standard holding patterns for air traffic in busy areas (like around major hub airports) are circular or teardrop shape. If you only view part of one, or if only part of the airspace the holding pattern is in is conducive to contrail formation, you could wind up with half circles, arcs, U-shapes, and so forth. I once saw a photo that supposedly documented two circular “chemtrails” over the north side of Chicago. I pulled out a copy of a chart and, sure enough, right where there’s a standard holding pattern for O’Hare. ---
**Author:** ![Irishman](https://avatars.discourse-cdn.com/v4/letter/i/b487fb/32.png) [@Irishman](https://boards.straightdope.com/u/Irishman)\ **Post date:** [June 1, 2011, 3:09am UTC](https://boards.straightdope.com/t/more-questions-regarding-chemtrails/580440/17 "2011-06-01T03:09:30Z")
What is your evidence these are “chemtrails” and not standard contrails? What is your evidence this is not the pattern of airlines traveling along similar flight paths approaching/departing an airport? ---
**Author:** ![user\_hostile](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/user_hostile/32/474_2.png) [@user\_hostile](https://boards.straightdope.com/u/user_hostile)\ **Post date:** [June 1, 2011, 3:44am UTC](https://boards.straightdope.com/t/more-questions-regarding-chemtrails/580440/18 "2011-06-01T03:44:33Z")
Well, I remember back in 1990, participating in a “chemtrail” spraying. I was flying either a DC-9 or a 727 and had flown out of Dulles heading for Minneapolis. We took off before dawn and as we got to altitude, the sun had risen. The plane was flying at the perfect angle: you could see the rear end of the engines on the wind, the heat distortion from the exhaust, and then the shadow of the contrail, excuse me, “chemtrail” forming. It only lasted for a couple of minutes before the sun climbed too high. Upon arrival at Minneapolis, I made contact with my handler and told him, “Operation TEH PWN is a success.” I was never heard from again. ---
**Author:** ![Floater](https://avatars.discourse-cdn.com/v4/letter/f/dc4da7/32.png) [@Floater](https://boards.straightdope.com/u/Floater)\ **Post date:** [June 1, 2011, 7:09am UTC](https://boards.straightdope.com/t/more-questions-regarding-chemtrails/580440/19 "2011-06-01T07:09:22Z")
> [@user\_hostile](#): > > I was flying either a DC-9 or a 727 As it’s impossible to see the exhaust from inside a DC-9 it was most probably a 727. ---
**Author:** ![user\_hostile](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/user_hostile/32/474_2.png) [@user\_hostile](https://boards.straightdope.com/u/user_hostile)\ **Post date:** [June 1, 2011, 5:00pm UTC](https://boards.straightdope.com/t/more-questions-regarding-chemtrails/580440/20 "2011-06-01T17:00:44Z")
> [@Floater](#): > > As it’s impossible to see the exhaust from inside a DC-9 it was most probably a 727. How so?😕 ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [June 1, 2011, 10:41pm UTC](https://boards.straightdope.com/t/more-questions-regarding-chemtrails/580440/21 "2011-06-01T22:41:38Z")
> [@charlespearl](#): > > Chemtrails over Chicago Suburbs > > Chemtrails Chicago Illinios on May 10, 2011. Please look at the photos I took on > > [http://www.flickr.com/photos/60217870@N06/](http://www.flickr.com/photos/60217870@N06/) > Date: 05-10-2011 > Time: 6:00pm - 9:00pm CST > Buffalo Grove, IL > County: Cook County > State: Illinois > Country: United States > Latitude: 42.1513889 > Longitude: -87.9597222 > > Many single trails and a few dual trails flying east/west in parrallel lines over a 3 hour period. This is one day before some big thunder storms. They fly extreemly close when crossing each other in the sky. The single trail jets fly extreemly fast. Good god, Buffalo Grove is only 6 miles from Chicago Executive Airport, which has a lot of business jet traffic. They’re freakin’ contrails, OK? They’re east-west and north of Chicago Executive to avoid O’Hare traffic, and parallel because airplanes tend to fly through the same airspace with a set separation. For Pete’s sake, saying these are some black ops chemical spraying is just stupid. :rolleyes: ---
**Author:** ![TSBG](https://avatars.discourse-cdn.com/v4/letter/t/77aa72/32.png) [@TSBG](https://boards.straightdope.com/u/TSBG)\ **Post date:** [June 1, 2011, 10:53pm UTC](https://boards.straightdope.com/t/more-questions-regarding-chemtrails/580440/22 "2011-06-01T22:53:18Z")
> [@user\_hostile](#): > > How so?😕 Because the engines on DC-9s are tail mounted, if that’s the right way to phrase it. EDIT: Although now I see the 727 engines are also…so I don’t know. [Next page](https://boards.straightdope.com/t/more-questions-regarding-chemtrails/580440.md?page=2)