Metallic photos of the sun by renowned photographer Greg Piepol bring together the best of art and science. Buy one or a whole set. They make a stellar gift. | | |
SDO SUNDOG MYSTERY: One year ago, NASA's Solar Dynamics Observatory amazed observers when it destroyed a sundog en route to orbit. A new analysis of the event is shedding light on the surprising way rocket shock-waves interact with clouds. Get the full story from Science@NASA.
EARTH-DIRECTED SOLAR FLARE: On Feb. 13th at 1738 UT, sunspot 1158 unleashed the strongest solar flare of the year so far, an M6.6-category blast. NASA's Solar Dynamics Observatory recorded an intense flash of extreme ultraviolet radiation, circled below:
The eruption produced a loud blast of radio waves heard in shortwave receivers around the dayside of our planet. In New Mexico, amateur radio astronomer Thomas Ashcraft recorded these sounds at 19 to 21 MHz. "This was some of the strongest radio bursting of the new solar cycle," he says. "What a great solar day."
Preliminary coronagraph data from STEREO-A and SOHO agree that the explosion produced a fast but not particularly bright coronal mass ejection (CME). The cloud will likely hit Earth's magnetic field on or about Feb. 15th. High-latitude sky watchers should be alert for auroras.
The source of this activity, sunspot 1158 is growing rapidly (48 hour movie). The active region is now more than 100,000 km wide with at least a dozen Earth-sized dark cores scattered beneath its unstable magnetic canopy. More Earth-directed eruptions are likely in the hours ahead.
THE PERFECT VALENTINE'S GIFT: How about a plane ticket to Norway? A solar wind stream due to brush past Earth's magnetic field around Feb. 14th could spark romantic lights around the Arctic Circle. Gabi and Gunter Reichert send this preview from Henningsvaer, a fishing village in Norway's Lofoten islands:
Note the wildlife in the foreground. "We were taking pictures of the Northern Lights on Feb. 10th when this fox strolled right into our photo," say Gabi and Gunter. "He looked at us from a distance of 4 or 5 meters, yawned, and then laid down. We illuminated him with a little lamp to get this composite of green auroras with a red onlooker."
Aurora watchers red and otherwise should be alert for polar geomagnetic storms next week. Aurora alerts make a nice Valentine's Gift, too: text or voice!
more images: from Valentin Jiganov in the Murmansk region of Russia; from LeRoy Zimmerman of Ester, Alaska; from Øystein Ingvaldsen of Norway; from Maxim Letovaltsev in the Hibiny mountains of Russia; from Chad Blakley of Abisko National Park, Sweden; from Hinrich Baesemann of Tromsø, northern Norway;
February 2011 Aurora Photo Gallery
[previous Februaries: 2010, 2009, 2008, 2007, 2006, 2004, 2003, 2002]
