I need to figure out some things for a book I'm writing. The first question is the easy one:
If I'm standing on a level plain, and an airplane flying at 40,000 feet passes, leaving a contrail, what's the maximum distance at which I could see it?
The easy answer comes from calculating the distance to the horizon
when at 40,000 feet, and that answer is: 245 miles.
I've read that "dust and water vapor in the air will rarely let you see more than 12 miles," but I know I've seen snow on the Sierra Nevada mountains from Mt. Diablo in the Bay Area, and that's a distance of at least 180 miles.
So I'm guessing 200 miles is a good answer. Thoughts?