HERE COMES THE SOLAR WIND: Solar wind flowing from a hole in the sun's atmosphere is approaching Earth. Estimated time of arrival: Sept. 1st. High-latitude sky watchers should be alert for auroras later this week when the gaseous material buffets Earth's magnetic field. Free: Aurora Alerts
THE END OF THE SOLAR ECLIPSE: One week ago today, the Moon passed in front of the sun producing a total eclipse visible from coast to coast in the USA. Here is how the magical minutes of totality ended, as recorded by Kenneth Edwards in Casper, Wyoming:
Pink hydrogen-filled prominences are visible along the edge of the sun just before the Moon moves away to reveal the glaring inferno below. Rays of sunshine lance through gaps in the Moon's mountainous terrain, creating "Baily's Beads" and the "Diamond Ring" effect. Not a bad way to wrap up a total eclipse.
AURORA SEASON IS BEGINNING: For reasons researchers do not fully understand, the weeks around equinoxes have more geomagnetic disturbances than any other time of year. In other words, auroras love equinoxes. We are now just weeks away from the northern autumnal equinox and, right on cue, the auroras have appeared:
Danilo Roncato and Paolo Bardelli took this picture on Aug. 25th from the window seat of a plane flying 38,000 feet over Greenland. "The auroras were very far away, but clearly visible through the windows," say Roncato and Bardelli, who captured the green glow using a 1 second exposure at 6400 ISO."
In addition to the equinox effect, it also helps that Arctic skies are darkening as the midnight sun sets after a long summer. Midnight is once again becoming a velvety-dark canvas where solar wind can paint the Northern Lights. Browse the aurora gallery for recent sightings --and stay tuned for more.
SPRITE-Y NIGHT IN SLOVAKIA: It was a dark and stormy night. After sunset on Friday, Aug. 18th, photographer Ondrej Kralik was hiking through the Low Tatras, a mountain range in central Slovakia. He could see stars overhead, but the horizon was flashing with the impulsive glow of lightning. "I thought a storm was coming," says Kralik, who trained his camera in the direction of the flashes. Instead of capturing the downward strike of lightning, however, he saw sprites:
"I quickly realized that the storm was far away, and I could see over the top of the thunderheads. Sprites were dancing along the cloudtops," says Kralik. "I saw this bright cluster of sprites with the naked eye and my camera captured it as well. Its brightness is approximately -6.7 mag, and it was located about 510 km far above southeast Germany."
"In the foreground under the sprites you can see the main ridge of Low Tatras, (Chabenec 1995 m) and Kotliska (1937 m) on the left," he says. "I was lucky to witness one of the brightest sprites, but as they say, fortune favors the prepared."
Sometimes called "space lightning," sprites are a true space weather phenomenon. They inhabit the upper atmosphere alongside auroras, meteors and noctilucent clouds. Some researchers believe they are linked to cosmic rays: subatomic particles from deep space striking the top of Earth's atmosphere produce secondary electrons that, in turn, kickstart sprites in the highly-charged environment above thunderstorms.
The link to cosmic rays is particularly interesting at this time. For the past two years, space weather balloons have observed a steady increase in cosmic rays penetrating our atmosphere. This increase is largely due to the decline of the solar cycle. Flagging solar wind pressure and weakening sunspot magnetic fields allow more cosmic rays into the inner solar system--a trend which is expected to continue for years to come. So stay tuned for more sprites.
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