ST. PETERSBURG, Fla. — We had a special treat Wednesday morning due to noctilucent clouds that are rarely seen in the Florida sky.
Noctilucent clouds are a part of a celestial phenomena usually found near the Arctic Circle during the summer. They form on the edge of space where temperatures are a bone-chilling -120°C (-184°F). At these extreme altitudes, water vapor condenses onto tiny particles — often meteoric dust or volcanic debris — forming minuscule ice crystals, which gives them a radiant glow as they reflect sunlight.
On Wednesday morning over the Florida sky, we got to witness this amazing glow due to increased water vapor from a Space X launch. The noctilucent clouds were visible well before the first sunlight because they were forming from the exhaust of the rocket more than 200,000 feet in the air, so while the sun had not risen for us, it was able to reflect off those clouds.
But why did they glow?
The answer lies in their unique positioning. As the sun dips below the horizon, its rays continue to illuminate these high-altitude clouds, while the lower atmosphere remains cloaked in darkness. The ice crystals scatter sunlight, producing their characteristic iridescent blue hue. This striking color arises because the small size of the ice particles efficiently scatters shorter blue wavelengths of light.
Hence the term "noctilucent," which means "night shining."
