Astro Bob: Encounter with a rogue contrail

We’re all familiar with the white trails that follow in the wake of high-flying jet airplanes. These temporary clouds are known as contrails and were first reported by high-altitude planes in the 1920s. That’s nearly 100 years ago. I emphasize their age because some people make a lot of hay with conspiracy theories that contrails are chemicals sprayed into the atmosphere meant to hurt us in some way. Other than deliberate attempts to attempt to create precipitation under certain circumstances, contrails are harmless and a natural consequence of high-flying aircraft.

Each engine of a passing jet aircraft leaves a trail of condensing water vapor as it flies through the cold air near the top of of the troposphere, the lowest layer of the atmosphere. Contributed / Bob King

The trails are made of water vapor and soot that are produced by burning jet fuel and exactly mimic the “contrails” of vapor pouring out of your automobile tailpipe on a frigid morning. Or for that matter when you exhale after breathing cold air. Most jets fly at an altitude of around 35,000 feet (11.9 km), where the

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