Something unusual is happening in the upper part of the earth’s atmosphere. Luminous Clouds (NLC) are forming and people can see them from the ground, although it is only May now. Andy Stables sent this photo from the Isle of Skye, Scotland, taken on May 26th.
The electric blue ripples “were clearly visible to the naked eye,” Stables says. “This is the earliest appearance of noctilucent clouds that I have seen here in Scotland.”
The NLC are the tallest clouds on Earth. Seeded by meteoroids, they hover at the edge of space about 83 km above the ground. Clouds form when summer plumes of water vapor rise into the mesosphere, allowing water to crystallize around meteorite smoke particles. The season for bright NLCs, visible with the naked eye, usually runs from June to August.
The NLC is starting early this year. Scientists have already received numerous reports of observations in Europe from latitudes up to 50 degrees, and, according to NASA’s AIM spacecraft, the clouds are rapidly increasing. In just 4 days after the clouds were first noticed, their area in the Arctic has increased 10 times:
More water in the mesosphere could be the reason: NASA satellite data shows that 2021 is one of the wettest years since 2007.
In recent years, summer noctilucent clouds have penetrated south to Los Angeles and Las Vegas, setting records for sightings in low latitudes. 2021 could be that year.
Observer tip: Look west over 30 minutes after sunset. If you see glowing blue and white streaks spreading across the sky, you may have noticed noctilucent clouds.