Why contrails hang around.
- By Mariana Gosnell
- Air & Space magazine, July 2007
(Page 2 of 2)
There are those who consider contrails to be downright sinister: noxious chemicals sprayed from aircraft to sicken populations and alter weather patterns, according to conspiracy theorists. The claims seem to rest on the notion that thin, short-lived contrails may consist of ice crystals, but the thicker, long-lived ones are not. In reality, the expanded lines are merely contrails that have evolved.
When U.S. air traffic was grounded for several days after the September 11, 2001 attacks, and the only contrails on satellite images were ones made by six military aircraft, NASA had a chance to see the difference the streamers make. Within five hours, the contrails from the six jets had expanded to cover 8,000 square miles. �