Allright, I know its been a while since this topic was brought up, but my friend Carl was trying to tell me that the government is conducting a series of experiments on the citizens of our fine country(U.S.) whereby they fly over the town where you live and dispense vast clouds of infection laden gas/whatever.
He’s convinced that once were all immune to the flu/rabies/aids/ingrown toenails we’ll all be safe from the real attack that they have planned for the rest of the world.
Either that or they plan to have plausible deniability when they finish their"testing" and unleash pandoras box on us. He said something about the Nixon administration and the need to lose a few billion of the earths human population.
What the fuck was my friend talking about , anyway?
Yeah, yeah, I did the Google search, but I don’t listen to Art Bell either…Just help me cut to the chase will you, I trust ya’ll for that, Y’know?
If your friend is referring to the contrails that high flying aircraft produce, I am not particularly worried. Water is one of the products of combusting hydrocarbons (jet fuel). When it initially exits the engine of the aircraft it is in the form of (invisible) steam. In the cold air of high altitudes the steam condenses into tiny water droplets and/or ice crystals, which reflect/refract/scatter sunlight to appear as white cloud trails.
If he is talking about something else, do let us know.
The conspiracy theory is that the government or some other covert group is dumping something out of airplanes which is disguised as the usual contrail, but actually contains some other substance…vaccines, infectious diseases, pesticides, or whatever, depending on who’s telling the story.
I think this is one of the more dubious conspiracy theories out there. I haven’t done loads of research on it, but everything I’ve read seems to indicate that spraying something out of high-altitude airplanes is a lousy way to spread it with any accuracy. So, I tend to doubt the idea that anything is being sprayed. You never know, but it seems implausible to me.
This whole thing does beg a question though, which is: What’s the explanation for some of the photos circulating on the internet? I’ve seen some pretty interesting shots showing literally dozens of huge contrails crisscrossing the sky in nearly perfect grid patterns. Since I believe (correct me if I’m wrong) that the intensity of a contrail is related to the altitude of the aircraft (not linearly related, but depending on the weather conditions at the time), it seems unlikely that so many planes would be travelling at the same altitude, at the same time, on such rigorous flight paths as to leave that sort of pattern.
Of course, that question does nothing to bolster the idea that there is anything unusual in these contrails; it just asks why the heck they’re there at all.
-Andrew L
Cecil talks about it http://www.straightdope.com/columns/000616.html
And further discussion about that column http://boards.straightdope.com/sdmb/showthread.php?threadid=98954&highlight=chemtrails+conspiracy
Crank-dot-net has a collection of sites on the subject. In the old days, loonies would get on a soapbox in the park. Nowadays, since soap manufacutrers have consipred to limit free speech by packing soap in light-weight cardboard boxes, the loonies have been obliged to get themselves websites.
As to the Nixon administration allegedly pruning the population tree… how many more does the world have now? Almost another billion?
If you are talking about the contrail from airplanes, than that is likely to be a crock. There is evidence, the government has admited as much, that back in the 1950’s chemicals were sprayed on civilian populations to see how they spread. I can’t find my links on the subject right now, but I do know that in Minneapolis there are areas that were subjected to the spraying that show higher rates of some rare cancers than average.
I want one of the chemtrail conspiracy theorists to explain why I’ve viewed contrails from the deck of a cruise liner way out at sea; are the planes spraying mind-control chemicals on the fish?
There are in fact flight paths that airplanes follow, and guidlines for altitude as well, that describe what amounts to a highway in the sky. Airliners will all follow the same routes as long as they are headed in the same general direction, so you’ll see lots of contrails in the same vicinity quite often.
See an example of a sectional aviation map at:
http://www.avmap.bizland.com/LA/la13.htm
Note the blue circles with degree marks on them and the faint blue lines connecting them with names like “V 370” or “V16-372”. These are flight paths that airplanes will follow. If you go to a major intersection of these paths, you’d see lots of planes pass. If contrails are forming, you’d see lots of contrails.
As for the “intensity” of a contrail, it does vary a bit but once you’ve condensed all the water vapor out of the plane’s exhaust, it can’t get any more intense. So, the main variable is how long the contrail stays around before disappearing. It is quite possible under some weather conditions that airliners at all common cruising altitudes will leave nearly identical contrails which will last all day long.
Because there are normal contrails as well as the secret sort 
.
Okay, as adam says, it’s probably/is a crock. Having said that, I’d bet most people in 50s & 60s USA believed that their government would never experiment on them and regarded all conspiracy theories as hogwash.
Same goes for all those poor (black) saps who thought that they were getting treatment for their syphilis. It’s an attitude that we like to think no longer exists and we’re probably right?
Another reason for regularly spaced lines is this:
A plane flys along a specific flightpath, leaving a contrail.
At this particular altitude, there is a crosswind; the contrail moves to one side at a constant speed.
A little later, Another plane flies the same route, leaving a parallel trail.
The crosswind continues to blow.
At an interval almost exactly the same as the last, another plane flies the same route etc.
(It’s should not be at all surprising that planes are passing through the same bit of sky on a regular basis; air traffic control plans it that way as a safe alternative to letting them all fly wing-to-wing).
Mangetout-
That blow-by effect is a nice hypothesis. I hadn’t thought of that.
-Andrew L