Monday, October 27, 2014
Two Short Parallel Contrails in a Cloudless Night Sky
While walking the dog around the block around 9:30pm, I looked up at the usually not very interesting New Jersey night sky and saw two short, narrow, parallel, contrail-like slashes in an otherwise cloudless sky. By the time I got home and got a camera, they had drifted southeast towards the horizon.
Throwing a cluster of words similar to the title of this post into the googlesphere yielded first this post, and then this one, on a site called contrailscience, which gives a logical explanation: jets descending through a relatively thin layer of moisture. The lines are oriented towards Newark/New York, and an additional possibility is that the jets entered the layer of moisture, then turned off their engines as they began coasting in to the airport from about fifty miles out. We hear this frequently over Princeton--what sounds like downshifting as a jet flies over.
Posted by Steve Hiltner