Contrails or Chemtrails?

I just returned from doing some errands on a beautiful fall day. While out, I noticed an unusual amount of planes and contrails in the sky. I started to think about that old controversy (or possibly urban legend) of chemtrails. Was what I saw in the sky really contrails, or possibly chemtrails? I thought this might be a good subject to look into again as some of the facts might have changed over the past few years.

First a bit of science. The word contrail is short for "condensation trails". They are long thin artificial clouds that sometimes form behind aircraft. A condensation trail, also called a vapor trail, forms at altitudes above 25,000 feet in temperatures below -40 degrees when engine exhaust condenses into ice crystals, creating an artificial cirrus cloud. Water is produced by hydrocarbon burning engines in about the same quantity as fuel consumed, and in the right conditions, this extra addition of water into the air pushes the water vapor past the saturation point, and condensation occurs.

Now I will go from science to possible science fiction. There are quite a few people that believe in a chemtrail conspiracy theory. This theory holds that some trails left by aircraft are actually chemical or bio agents deliberately sprayed at  high altitudes for unknown reasons. Some believe this is part of a clandestine program directed by some nefarious government official. To say the least, this theory is not accepted by the scientific community even though it lights up the blogoshpere on occasion.

It can get more bizarre. For example, since 1997, some believe we are breathing a cocktail of Ethylene Dibromide, Virally Mutated Molds, Nano-Particulates of Aluminum and Barium and so on and so on. As the story gets stranger, some believe self-replicating nano-machines and tiny parasitic nematode eggs and other very weird and unpronounceable things are also present in these mysterious chemtrails.

I have searched high and low on the internet and found many different theories on what chemtrails are. They range from part of the former "Star Wars" program to HAARP to alien technology to prevention of global warming. In short, chemtrails can be whatever the imagination can conceive. It is fascinating though to think why so many think these trails are something other than water vapor produced a high altitude by an aircraft engine. My theory is that people today are so distrustful of their own government, logic can take a back seat to legend. Do I think it is possible that contrails are really something else, possibly sinister. Sure, I think that is possible, but at this point I don't think probable. I still believe enough in our government that they would not intentionally do its citizens harm.

So when I look up in the sky on these beautiful autumn days and see the white lines crossing the azure blue sky, I will continue to believe I am seeing the evidence of many jets at different altitudes going many different places. However, that quiet still voice inside of me will always wonder "and what if they are not...".