BIG SUN-DIVING COMET DISCOVERED

What's up in space

spaceweather/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. MAGNETIC QUIET: The solar wind blowing around Earth is thin and steady, which means it is doing little to rattle our planet's magnetic field. Geomagnetic storms are unlikely during the next 24 hours. EMERGING BLAST SITE: A farside sunspot that exploded and hurled a bright CME into space on Sept. 23rd is now rotating onto the Earthside of the sun. NASA's Solar Dynamics Observatory photographed the emerging blast site during the early hours of Sept. 26th: Because the sunspot is still near the sun's eastern horizon, foreshortening prevents a clear view of its core magnetic structure. The events of Sept. 23rd, however, suggest that this could be a potent active region. Stay tuned for updates as the sunspot turns toward Earth. Solar flare alerts: text, voice. 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 Aurora Photo Gallery Realtime Noctilucent Cloud Photo Gallery [previous years: 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2011] Near Earth Asteroids Potentially Hazardous Asteroids (PHAs) are space rocks larger than approximately 100m that can come closer to Earth than 0.05 AU. None of the known PHAs is on a collision course with our planet, although astronomers are finding new ones all the time. On September 27, 2012 there were 1332 potentially hazardous asteroids. Recent & Upcoming Earth-asteroid encounters: Asteroid Date(UT) Miss Distance Mag. Size 2012 SZ2 Sep 19 8.2 LD -- 38 m 2012 RK15 Sep 24 8.2 LD -- 88 m 2012 SL50 Sep 27 2.8 LD -- 23 m 2012 SY49 Sep 28 2.6 LD -- 31 m 1998 UO1 Oct 4 60.1 LD -- 2.1 km 2005 GQ21 Oct 12 77 LD -- 1.0 km 1998 ST49 Oct 18 28.7 LD -- 1.3 km 1991 VE Oct 26 34 LD -- 1.1 km 2001 CV26 Oct 30 68 LD -- 2.4 km 2007 PA8 Nov 5 16.8 LD -- 2.4 km 2010 JK1 Nov 25 9.3 LD -- 56 m 2009 LS Nov 28 55.2 LD -- 1.1 km Notes: LD means "Lunar Distance." 1 LD = 384,401 km, the distance between Earth and the Moon. 1 LD also equals 0.00256 AU. MAG is the visual magnitude of the asteroid on the date of closest approach.