POSSIBLE GEOMAGNETIC ACTIVITY THIS WEEK: Solar wind flowing from a southern hole in the sun's atmosphere could graze Earth's magnetic field later this week, probably on Dec. 4th. No geomagnetic storms are expected. However, Arctic auroras will brighten when the solar wind arrives. Aurora Alerts: SMS text
POLAR STRATOSPHERIC CLOUDS: The Arctic season for polar stratospheric clouds has begun. "The rare clouds made their first appearance over Stockholm earlier this afternoon (Dec. 2nd) and shone brightly against the evening sky," reports photographer Peter Rosén, who had no trouble seeing the clouds from the brightly-lit downtown area of Stockholm:
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, as shown in this close-up from Peter Rosén:
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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A MOONSTONE AT THE EDGE OF SPACE: Are you looking for a far-out gift? Nothing says "Merry Christmas" like a gem from the edge of space. The students of Earth to Sky Calculus flew this moonstone wrapped in a hand-crafted sterling silver Celtic love knot 35.1 km (115,158 feet) above Earth's surface:
You can have it for $179.95. The students are selling these pendants to support their cosmic ray ballooning program. Each one comes with a greeting card showing the item in flight and telling the story of its journey to the edge of space. All sales support the Earth to Sky Calculus cosmic ray ballooning program and hands-on STEM research.
Far Out Gifts: Earth to Sky Store
All sales support hands-on STEM education
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