Contrails: Do some of the white condensation trails, that airplanes are spreading over our skies, contain chemicals in excess of the fuel combustion in the exhaust? What is the purpose of these "Chemtrails"?

There is a real problem with your statement if I understand it correctly. You seem to imply that chemicals are coming into existence from nowhere?   I'm not willing to watch your conspiracy theory videos, but the idea of chemicals popping themselves into existence isn't science.  Or reality. There is a science law I teach in chemistry.  It is the law of conservation of matter.  The mass going into a reaction is the same as the mass going OUT of a reaction.  Matter cannot be created or destroyed in ordinary chemical reactions.  The idea that chemicals are somehow being created on the fly is silly.  Silly in the sense that matter can't be created in normal chemistry. On the other hand, it would take almost nothing to examine the chemistry of fuels consumed in airplanes and examine the contrails.  If you assume something GETS introduced while the plane is in flight (some tube?  squirts chemicals in the exhaust?)  Then you would have to have thousands upon thousands of plane mechanics in on the conspiracy since they take care of these flying machines.  I know some of them and I can only say that the idea that they are in on some great conspiracy is just stupid. Can we some day try to combat global warming with chemical contrails (most likely sulfurous compounds)?  ABSOLUTELY, but are we doing it now?   Nah.   We aren't sure how workable it would be and there might be far worse consequences.  We are looking into it and the science behind it is worth considering, but we are just asking the questions for now.  Go put your tin hat back on and try to hide from the brain control of microwave towers (which I doubt you even understand how they work).    I can't believe I even wrote an answer for such foolishness.   I guess I'm the real idiot here.

Why would you release chemicals into the air when you are an air-breather yourself?

Blah, I'll reverse the argument that almost everyone is against. I don't call them Chemtrails. I call it spraying, that happens in the Contrail. There is plenty of proof that it is true. In fact the only ones that call it a Conspiracy anymore are the nuts that won't let it go. The fact is Geoengineering is being used here in the US and around the world. President Obama signed it into law with I might point out NO resistance from Congress, the ACDC ACT. So what is the ACDC ACT? It is an attempt to Geoengineer the environment to slow down degradation of the atmosphere. Global Warming, CO2 emissions, etc... It was passed with no resistance from Congress, Republicans or Democrats. In fact Former Vice President Al Gore was right in his belief that matters need to be taken in hand. So what are the signs? The arctic for sure. Look up any maps of the Arctic from the past and current, the view is scary when you consider how much Ice has melted. If you look here in the US you search mountains from years ago and now and what do you see? Very little to NO show. So what causes this? So the problem is man made and it is not getting better. Well not for some. In California they have drought, In the center of the US you have more extreme Tornado's, on the East Coast and Southern States more powerful hurricanes. What could cause this? Nature sure, but it's a man made alteration. The Jet stream has been moved. What? Don't believe search the Jet Stream past and present. So how to move a Jet Stream? Pressure! Create a high pressure pocket and the air moves around it or put them in different places and you can compress it. What can do this? Well Hot and Cold of course or you could spray a mix out of planes that would allow this to happen. It is being done. The best way is to spray Aluminium and Bromine and heat it. What you get is a very lite  powder substance microscopic in nature that floats for 4 to 8 hours. It is quite slick idea. Even though the environmental damage can be substantial over time. So how do you identify it? Easy actually, the Military and Civilian planes spray it either out the exhaust or nozzle on the wings or tail, since it needs to be heated to spray. Everyone says contrails remain in the sky. That's not true. Aircraft exhaust is condensation, but like all condensation it evaporates. Sure it can remain in the air for a few minutes, but it still breaks down. And note: They no longer dump fuel out of commercial airlines to land. The spray in the sky makes the sky turn WHITE! Why? Simple Silver and gray reflect on the sun looks? White... So if you watch a contrail being sprayed and it doesn't disappear in say 15 mins and it crosses the sky completely from one end to the other, it is spraying. Now watch it or get a camera and look for 4 to 8 hours. What happens? It's spreading out. 1st twice the size then several times, until the sky starts turning white. When condensation spreads it dissipates and does not expand indefinitely, it evaporates. Not so with spraying. It will disappear, but what you cannot see doesn't hurt? Right? Not so much! The spray is microscopic and the reason you can see it, is because the light is reflecting on it. What the naysayers have missed is the facts that have been presented. So what you do is look up these topic and judge for yourself. Don't expect naysayers to ever be open minded to facts. Search: ACDC ACT Geoengineering (Even though I don't like the term) Chemtrails Arctic Maps Past and Present USA Maps past and present (This is a weird term i never use) Alumina UK Questions US Geoengineering. Etc... This is no small feat and they are not hiding it. They just are not talking about it.

If the trails are just water vapor, why can there be two aircraft nearly the same altitude and flight path, one leaving a trail that merges with other trails to form haze, while the other trail dissipates like water vapor is supposed to? And why ate there trails one day and not the next, then trails again? Do no plans fly that day?

There is a difference between Contrails and what people call Chemtrails. Contrails dissipate whereas the Chemtrails linger slowly spread out and form an unnatural cloud formations. Our governments do acknowledge the existence of Geo-Engineering, (Weather Modification). I personally do not advocate any one explanation offered by the numerous conspiracy theories. The above video Why on Earth are they Spraying? Contains numerous theories and potential explanations. With the level of misinformation provided by official bodies and conspiracy theories it would be obtuse to say what is true. I do feel though that it is right for transparency and independent investigation regarding Geo-Engineering.  

OK I'm giving my answer, strting from this interesting documentary Obviously no one with a good governmental or semi governmental position would expose him self admitting that spraying chemicals over the skies could be reality. Many are thinking, following Occam's razor principle, that: Why there should be chemicals inside a con-trail if the phenomenon is perfectly justified by science and if is more than enough the presence of vapor and combustion exhaust to form it? Absolutely, we live in a world of government totally transparent and reliable, where Wars are things of paleolithic and human right (and our Planet right) reign among all, evident no? so we can stay peaceful, that's totally right. In any case, to let me doubt about Chemtrails (or skies spraying in some other "cool" way) could ... unfortunately ... be currently reality, is enough this assertion of 2 years ago: and what about this?! (so all the expert here up with many upvote have a reply?)

Why do contrails sometimes persist and grow? My feeling is that stating that they will, only if the humidity is high enough, isn't really that satisfactory. Of course, high humidity is required for exhaust to mix with clear air to form a contrail. But, once they form, mixing of saturated cloudy air with subsaturated surrounding clear air, will only yield subsaturated air, and hence evaporation. Actually there is some thought that non-vapor chemicals might be involved, that coatings of nitric acid might inhibit evaporation: see the paper in Science http://www.sciencemag.org/content/303/5657/516.short But, personally, I think this misses the main mechanism. Once a contrail forms, it cools because ice crystals emit thermal radiation to space *much* more effectively than surrounding clear air. This creates a pressure difference between the contrail and it's environment, and so the contrail spreads into the environment, meanwhile creating air circulations within the cloud. Some fraction of these air circulations creates new contrail cloud, more cooling, more spreading, and so on. A positive feedback. And voila, CIA mind control of the American populace. This spreading doesn't always happen very effectively, however, because some of this continually generated turbulence within the cloud mixes in dry air. If the air is too dry, the aforementioned positive feedback is overwhelmed. Precipitation of ice crystals can also lead to the appearance of spreading, but I think radiatively driven spreading is the main mechanism.

Let me ask you this.  If the governments of the world were dumping chemicals in the atmosphere, why would you care?  I would care if those chemical were in the air I breathed, the water I drank, or the food I ate.  In short, if the chemicals dumped via 'chemtrails' worked their way down to the ground and into my personal consumption.  But if they did, I could demonstrate that by testing the air, water, or food around me for their presence.  Many people conduct tests of this kind quite frequently, all over the world.  Why don't you go look at what their tests uncover?

There is another phenomenon going on which has so far gone unmentioned. The apparent segregation of the contrail into a diffuse component and a consolidated, persistent component (as shown in the first video) is as innocuous as it is real and easily explained. As the plane flies, its engines are spewing out the mix of gases and particulate that Robert details. The wings are contributing another phenomenon: behind the wings are entrained two* very large-scale trailing vortices. When viewed from behind, the port wing has a vortex*** coming off with a clockwise rotation and the starboard wing has a vortex coming off with a counterclockwise rotation. There is a large amount of energy in these vortices - a significant fraction of the energy the aircraft uses in flight is directly turned into this motion; the pressure at their cores is quite low. Some of the exhaust condensation and particulate is entrained in the core or core region of this vortex, some of the exhaust is not. Until viscosity catches up with the inertial motion of the vortices (which takes enough time that the plane moves many dozens of miles away), the exhaust entrained in the vortices finds itself with a stable environment with a higher dewpoint than ambient (due to reduced pressure around the center of the vortex) and a pressure gradient working against diffusion and outwards convection (due to the core structure of the vortex). Consequently, it stays nice and bright white, in defined lines corresponding to the vortex pair, for many miles behind the aircraft. An aircraft with four engines still emits only two trailing vortices and on a clear day you can see the point where parts of the two exhausts per side consolidate into a single vortex core on each side of the aircraft - the consolidation, as far as I have observed, occurs within a few plane lengths. Eventually the vortices slow down and are chopped up by large-scale turbulence and wind shear, succumbing to convection and causing the water droplets to evaporate (depending on the humidity at the time, I suppose). Meanwhile the exhaust that was not entrained in the trailing vortices has convected away long ago, broken up by even slight winds, so that the water droplets do not form a very bright cloud even if they do not quickly evaporate. George *Depending what is meant by "two". It's one structure, with a center which trails parallel to the aircraft motion behind the wing on one side of the aircraft from infinity**, turns and goes through the whole wing/fuselage, and comes out the other wing, turning back to go antiparallel to the aircraft motion and off to infinity**. The structure I am describing is the set of what are described as "horseshoe vortices". **Not actually infinity, but close. The only reason they don't stop at infinity, or, say, a wall, is because of the viscosity of air which damps the motion and returns it to heat. Without viscosity, not only would they go off to infinity (or a wall), but the entire quantity of energy transferred from the engines to the vehicle in a certain amount of time would be found in the motion of the length of trailing vortex produced in that time. This is true for the same reason that the Maxwell-Faraday law is true - Stoke's theorem imposes a fixed "topology" on vortical structures. ***It's really not just one, and it's not emitted only from one location but sort of continuously along the trailing edge of the wing. A more accurate but less illuminating way to describe it would be "The trailing edge emits a bunch of vorticity, which convects together sufficiently rapidly that we can, on a scale slightly larger than the wing and corresponding to our fidelity when viewing a plane at altitude from the ground, think of this as a single vortex with one singular core or perhaps a Rankine vortex with the vorticity convecting around the minimum-pressure ring but the distinction is mostly irrelevant to the discussion."