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SOLAR ERUPTIONS: The far side of the sun is alive with activity. On Feb. 28th, NASA's twin STEREO spacecraft observed one and perhaps two clouds of material blasting away from a high-latitude, site not visible from Earth. The Solar and Heliospheric Observatory (SOHO) recorded a movie of the clouds billowing over the sun's northern limb. So far, none of this activity appears to be Earth-directed.
SNOW MOON: According to folklore, last night's full Moon was the "Snow Moon," named after the heavy snows of February. Snow was not required, however, for an apparition. Mark Staples sends this picture from Little Lake Santa Fe in central Florida:
"We didn't actually have snow, but it was cold," says Staples, who held up a life preserver to catch some moonlight. "The night before, temperatures dropped into the 20s. A local blueberry farm sprinkled water throughout the moonlit night to help save the crop. We'll find out in June if it worked!"
more images: from Pat Boomer of Red Deer, Alberta, Canada; from Martin Popek of Nýdek, Czech republic; from Tamas Ladanyi of Lake Balaton, Hungary; from Constantinos Emmanouilidis of Alikes, Volos, Greece; from David of Hudson, FL; from Tamás Ábrahám of Zsámbék, Hungary; from Ron Glasscock of Hurley, New Mexico
NOVEL USE OF A BUS STOP: In what appears to be an all-time first, nature photographer Monika Landy-Gyebnar of Veszprem, Hungary, has pioneered the use of a roadside bus stop as a solar spectroscope. "I was photographing a very intense halo display yesterday when I noticed a colorful flash from the corner of my eyes," Landy-Gyebnar. "It was coming from a bus stop across the street." Click on the image and behold the spectrum of the sun running along the bottom of the structure's cut-glass walls:
The dark gaps in the spectrum are real. They are Fraunhofer lines, named after the German physicist Joseph von Fraunhofer who studied them in the 18th century. Fraunhofer lines are imprinted on the sun's spectrum by cool gases in the sun's atmosphere, which absorb light from the hot stellar surface below. Each color corresponds to a specific element. The double-yellow lines caused by sodium, for instance, are particularly obvious in the bus-stop spectrum.
Fraunhofer lines have been used to study the chemical make-up of stars for more than two hundred years. Of all the stars in the heavens, however, only the sun is bright enough to show its spectrum in the corner of a bus stop. It's something to look for the next time you're waiting for a ride.
How does it work? Beveled edges outlining the bus stop's glass sides acted like a high-dispersion prism, spreading the colors of sunlight into a broad line for easy inspection. The relevant cuts are diagrammed here. "The sun was behind and above the bus stop at an elevation of 28-29 degrees," notes Landy-Gyebnar.
February Northern Lights Gallery
[previous Februarys: 2009, 2008, 2007, 2006, 2004, 2003, 2002]