I went out on my deck last night to check out the sunset, and saw this really weird cloud in the sky. It was like some kind of “bridge” between two other clouds. I’m talking about that strange linear structure you see near the center of this photo. Of course, I was curious what could have caused something like that.
This is one of the things I like about science. Whenever you observe something unusual, you know there’s some kind of logical explanation behind it. It might not be obvious at first, and there’s always the chance that it was just some “random” effect (especially with clouds). But even in the less-exact science of meteorology, there are laws that govern behavior, allow predictions, and provide explanations.
The first thing that came to mind was that some type of spurious updraft had deformed the lower cloud. Problem with that was, it’s not really oriented upward, and updrafts generally go “up.” The second thing I thought of was that it was a totally separate cloud forming over Lake Pleasant, which lies just beyond those mountains on the horizon. Problem with that was, the kinds of clouds that form from evaporated water over lakes are not typically shaped like that. They look more like this. Something about the shape of this cloud just wasn’t right.
Then it hit me. Not the cloud — the solution. What I was seeing was a contrail. This photo was taken during March, when the upper atmosphere is cooler and more conducive to contrail formation. Apparently, a jet flying from some point west of here was climbing to altitude, and passed through the same cooler-temperature air layer that allowed that lower cloud to form. The contrail ends where the atmospheric conditions change again, with the air becoming warmer and/or drier. Under the right conditions, contrails can arc across the entire sky. In this case, I was seeing only a section of a contrail where atmospheric conditions were just right.
Mystery solved. The perspective from my deck made it look like a “bridge” joining two separate layers of clouds, but the alignment was purely coincidence. If I had examined it through my telescope, that probably would have been obvious. Using only my eyes, I had been “fooled” by the chance alignment. Scientists are often misled by Nature.
Einstein once said, “God is subtle, but He is not malicious.” He often used “God” as a synonym for “Nature.” His actual words (in German) were: “Raffiniert ist der Herrgott, aber boshaft ist er nicht“. Try plugging that into Google Translate.
Einstein was not a particularly religious person. His own explanation of the quote was: “Nature hides her secrets because of her essential loftiness, but not by means of ruse.” He had a strong belief that the laws of Nature were self-consistent and knowable, but was acknowledging how those laws aren’t always obvious.
Next Week in Sky Lights ⇒ Mars at Opposition