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COOL VIDEO FROM THE ASTEROID BELT: A just-released video from NASA's Dawn spacecraft takes viewers on a beautiful flyover of the giant asteroid Vesta. Buckle your seatbelt and watch the movie.
GEOMAGNETIC STORM IN PROGRESS: As predicted by analysts at the Goddard Space Weather Lab, a coronal mass ejection (CME) hit Earth's magnetic field at ~03:30 UT on Sept 17th. The impact sparked a moderate geomagnetic storm (subsiding) and auroras around the Arctic Circle. John Dean sends this picture from Dexter, Alaska:
"The auroras were spectacular at times, with a lot of rayed bands, coronas and arcs," he says. "This is the first time I have ever seen auroras around me 360 degrees."
High-latitude sky watchers should remain alert for auroras tonight as Earth's magnetic field continues to reverberate from the CME's impact. Aurora alerts: text, voice.
more images: from Michael Kunze flying 30,000 ft over Greenland; from Chad Blakley of Abisko National Park, Sweden
September 2011 Aurora Gallery
[previous Septembers: 2010, 2009, 2008, 2007, 2006, 2005, 2004]
GOODBYE SUNSPOT 1289: This weekend, big sunspot AR1289 is approaching the sun's western limb where it will soon disappear from view. Jesús Carmona de Argila of Madrid, Spain, captured these parting shots on Sept. 17th:
The image on the left was taken through an "H-alpha" filter tuned to the red glow of solar hydrogen. It reveals a long magnetic filament trailing the sunspot's dark core. This structure has prompted some observers to nickname AR1289 "the tadpole." The image on the right was taken through a white light filter. It shows the sunspot as the human eye would see it if the sun weren't so blindingly bright. The departing sunspot, while photogenic, poses little threat for Earth-directed flares.
more images: from Jo Dahlmans of Ulestraten The Netherlands; from Gianluca Valentini of Rimini, Italy; from John Chumack of Dayton, Ohio; from Francois Rouviere of Mougins, France; from James Kevin Ty of Manila , Philippines
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 17, 2011 there were 1244 potentially hazardous asteroids. 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.
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| ||Researchers call it a "Hubble for the sun." SDO is the most advanced solar observatory ever. |
| ||3D views of the sun from NASA's Solar and Terrestrial Relations Observatory |
| ||Realtime and archival images of the Sun from SOHO. |
| ||from the NOAA Space Environment Center |
| ||the underlying science of space weather |
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