Well, there's aeronautical and meteorological science. Contrails are just another kind of cloud, and, yes,their appearance and disappearance depends on the weather conditions, particularly governing the level of absolute humidity that corresponds to 100% relative humidity. If the contrail exhausts into an atmosphere where there is still a ways to go before 100% relative humidity is reached, it will evaporate and fade away. If the contrail exhausts into an atmosphere that has already reached 100% relative humidity, it cannot evaporate and will persist.
I have watched aircraft fly overhead ever since I can remember. In my early boyhood (before reading) I watched B-47s and B-52s fly overhead, laying down a long, long contrail. Then, later, 707s and DC-8s. Same thing. As the engine technology changed from turbojets to turbofans, there was less moisture in the exhaust. Contrails became less evident. But as the aircraft began to fly at higher altitudes (35,000 feet +), the air was thinner and dryer. Just as it was when the military planes were flying from 40,000 to 50,000 feet. One spring day in 1970, a classmate and I were walking across campus and noticed a contrail streaking across the sky at an unusually high rate. We made the assumption that it was a military plane at ~50,000 feet and estimated the angular rate of progress and calculated a speed of about Mach 3. We concluded we had seen an SR-71. I am still content with that conclusion today, knowing now what its operational characteristics were.
Net result: yeah, contrails can be of different kinds....just like there can be different clouds.
Don't start saying that nothing would convince you, when you don't know the science behind the phenomenon. You wind up sharing the mind-set of the Moon Shot Hoax groupies. Since there is no evidence for chemtrails, you need to stop imagining them.
Well, there's aeronautical and meteorological science. Contrails are just another kind of cloud, and, yes,their appearance and disappearance depends on the weather conditions, particularly governing the level of absolute humidity that corresponds to 100% relative humidity. If the contrail exhausts into an atmosphere where there is still a ways to go before 100% relative humidity is reached, it will evaporate and fade away. If the contrail exhausts into an atmosphere that has already reached 100% relative humidity, it cannot evaporate and will persist.
I have watched aircraft fly overhead ever since I can remember. In my early boyhood (before reading) I watched B-47s and B-52s fly overhead, laying down a long, long contrail. Then, later, 707s and DC-8s. Same thing. As the engine technology changed from turbojets to turbofans, there was less moisture in the exhaust. Contrails became less evident. But as the aircraft began to fly at higher altitudes (35,000 feet +), the air was thinner and dryer. Just as it was when the military planes were flying from 40,000 to 50,000 feet. One spring day in 1970, a classmate and I were walking across campus and noticed a contrail streaking across the sky at an unusually high rate. We made the assumption that it was a military plane at ~50,000 feet and estimated the angular rate of progress and calculated a speed of about Mach 3. We concluded we had seen an SR-71. I am still content with that conclusion today, knowing now what its operational characteristics were.
Net result: yeah, contrails can be of different kinds....just like there can be different clouds.
Don't start saying that nothing would convince you, when you don't know the science behind the phenomenon. You wind up sharing the mind-set of the Moon Shot Hoax groupies. Since there is no evidence for chemtrails, you need to stop imagining them.