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SLIGHT CHANCE OF FLARES: NOAA forecasters estimate a 20% chance of M-class solar flares today. The most likely source would be sunspot AR1575, which is facing Earth squarely-enough for geoeffective eruptions. Solar flare alerts: text, voice.
POLAR LIGHTS: A medium-speed (~450 km/s) solar wind stream is brushing against Earth's magnetic field, sparking intermittent auroras around the Arctic Circle. Frank Olsen photographed these colorful streamers over Sortland, Norway, during the early hours of Sept. 27th:
"The auroras shone right through the bright moonlight," says Olsen. "It was a nice [little outburst]."
The display was not caused by a geomagnetic storm, but at this time of year no storm is required. For reasons researchers do not fully understand, equixoxes favor auroras. During the nights of early autumn, even a gentle gust of solar wind can ignite colorful lights at high-latitudes. Browse the gallery for current images:
Realtime Aurora Photo Gallery
BIG SUN-DIVING COMET DISCOVERED: Astronomy forums are buzzing with speculation about newly-discovered Comet C/2012 S1 (ISON). Currently located beyond the orbit of Jupiter, Comet ISON is heading for a very close encounter with the sun next year. In Nov. 2013, it will pass less than 0.012 AU (1.8 million km) from the solar surface. The fierce heating it experiences then could turn the comet into a bright naked-eye object. (continued below)
Comet ISON photographed by E. Guido, G. Sostero & N. Howes on Sept. 24. [more]
Much about this comet--and its ultimate fate--remains unknown. "At this stage we're just throwing darts at the board," says Karl Battams of the NASA-supported Sungrazer Comet Project, who lays out two possibilities:
"In the best case, the comet is big, bright, and skirts the sun next November. It would be extremely bright -- negative magnitudes maybe -- and naked-eye visible for observers in the Northern Hemisphere for at least a couple of months."
"Alternately, comets can and often do fizzle out! Comet Elenin springs to mind as a recent example, but there are more famous examples of comets that got the astronomy community seriously worked up, only to fizzle. This is quite possibly a 'new' comet coming in from the Oort cloud, meaning this could be its first-ever encounter with the Sun. If so, with all those icy volatiles intact and never having been truly stressed (thermally and gravitationally), the comet could well disrupt and dissipate weeks or months before reaching the sun."
"Either of the above scenarios is possible, as is anything in between," Battams says. "There's no doubt that Comet ISON will be closely watched. Because the comet is so far away, however, our knowledge probably won't develop much for at least a few more months."
Meanwhile, noted comet researcher John Bortle has pointed out a curious similarity between the orbit of Comet ISON and that of the Great Comet of 1680. "Purely as speculation," he says, "perhaps the two bodies could have been one a few revolutions ago."
Stay tuned for updates.
Realtime Space Weather Photo Gallery
Realtime Noctilucent Cloud Photo Gallery
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