SOLAR MINIMUM CONDITIONS ARE IN EFFECT: The sun has been without spots for 18 consecutive days--a sign that Solar Minimum is underway. Many people think Solar Minimum is uninteresting. Not so. This phase of the solar cycle brings extra cosmic rays, long-lasting holes in the sun's atmosphere, and a possible surplus of noctilucent clouds. Aurora Alerts: SMS text
POLAR STRATOSPHERIC CLOUDS: The Arctic season for polar stratospheric clouds has begun. "During yesterday's Biathlon World Cup premiere in Östersund, Sweden, I got to see my first PSCs for this season," reports photographer Göran Strand. "It was a really beautiful display of really bright PSCs mixed with ordinary clouds."
Polar stratospheric clouds are a sign that the Arctic stratosphere is getting cold. Very cold. They require temperatures around -85ºC to form.
The stratosphere is extremely dry, which makes it hard for clouds of any type to form. Only when the air up there becomes extremely cold do widely-spaced water molecules coalesce to form ice crystals--the "stuff" of PSCs. High-altitude sunlight shining through these ice particles produces the clouds' characteristic bright iridescent colors. People who see them generally agree, they are the most beautiful clouds on Earth.
"Polar stratospheric clouds far outshine and have much more vivid colours than ordinary iridescent clouds, which are very much poor relations and seen frequently all over the world," writes atmospheric optics expert Les Cowley. "Once seen they are never forgotten."
As the winter solstice approaches and plunges the northern stratosphere into deeper cold, these clouds will appear with increasing frequency. Arctic sky watchers, submit your photos here.
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DARTH VADER IN THE STRATOSPHERE: Impressive. Most impressive. On Nov. 2nd, the students of Earth to Sky Calculus launched a cosmic ray balloon to the stratosphere. Darth Vader went along for the ride, floating 109,580 feet above the rugged Sierra Nevada mountains of central California:
You can have him for $97.95. The students are selling Vader to support their cosmic ray ballooning program. This 5-inch tall blown glass ornament will look great on your holiday tree. It comes with a greeting card showing the Sith Lord in flight and telling the story of his journey to the edge of space and back again.
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All sales support hands-on STEM education
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