Chemtrails, short for "chemical trails," are a popular conspiracy theory that claims the long-lasting trails left by airplanes in the sky are not just condensation (contrails) but chemicals deliberately sprayed for various alleged nefarious purposes, such as weather manipulation, mind control, or population control. Scientifically, these trails are condensation trails formed by water vapor freezing around aircraft exhaust particles under certain atmospheric conditions, creating ice crystals that appear as white streaks. The theory started gaining attention in the mid-1990s, partly inspired by an Air Force research paper discussing future weather modification, though the EPA and scientific community have clarified no such chemtrail spraying programs exist. The science community overwhelmingly considers chemtrails a hoax, with explanations for persistent trails being natural atmospheric phenomena like humidity and wind conditions. Despite the conspiracy theory's popularity, especially on social media, extensive investigations and expert reviews have found no evidence supporting chemtrails' existence, and they have been dismissed as misinterpretations of ordinary contrails and cloud physics.
