RANDOM ACT OF METAPHOR: Vapour Trails

Hmmm, where does that vapour trail begin and end as it streaks across the clear, blue sky? Better question: How long will it linger after the jet that left its signature has passed out of our event horizon?

 

The first question is, of course, rhetorical. The second has deeper implications. According to Encyclopedia Britannica, these streamers of clouds – also known as 'condensation clouds' or 'contrails' – can last up to several hours. Elsewhere on the web I read that they can interfere with...