Chemtrails

The chemtrail conspiracy theory is the claim that long-lasting trails, so-called "chemtrails", are left in the sky by high-flying aircraft and that they consist of chemical or biological agents deliberately sprayed for unknown purposes undisclosed to the general public. Believers in the theory argue that normal contrails dissipate relatively quickly and that contrails that do not dissipate must contain additional substances. These arguments have been dismissed by the scientific community: such trails are normal water-based contrails (condensation trails) that are routinely left by high-flying aircraft under certain atmospheric conditions. Although proponents have attempted to prove that the claimed chemical spraying does take place, their analyses have been flawed or based on misconceptions.

Because of the persistence of the conspiracy theory and questions about government involvement, scientists and government agencies around the world have repeatedly explained that supposed chemtrails are in fact normal contrails.

The term chemtrail is a portmanteau of the words chemical and trail, as contrail is of condensation and trail. Believers in the conspiracy theory speculate that the purpose of the claimed chemical release may be solar radiation management,psychological manipulation, human population control, weather modification, or biological or chemical warfare and that the trails are causing respiratory illnesses and other health problems.

Chemtrail conspiracy theories began to circulate after the United States Air Force (USAF) published a 1996 report about weather modification. Following the report, in the late 1990s the USAF was accused of "spraying the U.S. population with mysterious substances" from aircraft "generating unusual contrail patterns." The theories were posted on Internet forums posted by people like Richard Finke and William Thomas; they were also discussed by late-night radio host Art Bell, starting in 1999. As the chemtrail conspiracy theory spread, federal officials were flooded with angry calls and letters.

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Wikipedia