By CLINT WILLIAMS via The Bellingham Herald
Look! Up in the sky!
It’s a bird!
It’s a plane!
It’s a chemtrail!
The chemtrail conspiracy theory claims that some contrails are chemical, biological or otherwise toxic elements sprayed at high altitudes by government agencies _ of some sort _ for the purpose of _ well, something not good. It’s high-altitude crop dusting for nefarious purposes, the tin-foil hat crowd claims.
Normal jet airliner exhaust contrails quickly dissipate, the conspiracy theory holds. Chemtrails _ which are loaded with toxic heavy metals and heaven knows what else _ linger in the sky for hours.
The theory has no scientific basis, writes Grant Petty, a professor of atmospheric science and the University of Wisconsin-Madison.
“The lifetime and behavior of contrails depend on the environmental conditions in which they form,” Petty writes. “Growing contrails result when the humidity at high altitudes is at or above the saturation point with respect to ice. So when condensation is injected in the atmosphere at those altitudes, the microscopic particles of ice don’t simply evaporate, they persist and even grow, and they are spread by the winds into broader patches of cirrus cloud.”
If persistent contrails are more common, Petty suggests, it is because there is more high-altitude airliner traffic and the stratospheric humidity is higher because of the moisture left by the contrails of all that traffic.
Also See: A Million Poisoning Planes