Serious question, why do some contrails hang around so long after a flight?

I was on a plane to Vegas last week and saw the trails behind us stay for ages. It made me remember talks about secret stuff from planes. Do you think there's a real explanation or something else going on?

3 comments

3 Comments

finley_lopez981mo ago

How long contrails last mostly depends on the humidity and temperature up there.

milabutler1mo ago

Contrails lasting a long time is all about the moisture and cold air up there. If it's really humid, the ice crystals from the engine exhaust spread out and stay visible. Seen it plenty on flights, and it's just normal science, no hidden agenda.

patricia9051mo ago

But what explains when those trails spread out and block the sun for HOURS? @finley_lopez98 mentioned humidity, but that seems too simple for such a big effect. Could there be other factors at play, like different engine types or flight paths?