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HISTORIC FIRST: For the first time ever, a spacecraft has gone into orbit around Mercury. NASA's MESSENGER probe is now circling the solar system's innermost planet, poised to reveal a world that is both akin to Earth and shockingly alien. Get the full story from Science@NASA.
MAGNETIC FILAMENT: A long and sinuous filament of magnetism is snaking over the sun's western limb. NASA's Solar Dynamics Observatory captured the 200,000 km-long structure in mid-twist on the morning of March 18th:
Long filaments like this one are often unstable. If this one erupts, it could hurl pieces of itself toward Earth. More likely, the filament will continue to wind over the western limb, active but intact. Either way it's a good show. Readers with solar telescopes are encouraged to monitor developments.
PARTING SHOT: Departing sunspot 1169 erupted during the late hours of March 16th and hurled a spectacular coronal mass ejection (CME) over the sun's western limb. Click on the image to play a movie of the expanding cloud:
Only a week ago, sunspot 1169 was squarely facing our planet. If the eruption had occurred then, we'd be expecting bright auroras and geomagnetic storms before the weekend. Instead, this CME will sail wide right of Earth with negligible effect. Maybe next time.
more images: from John Nassr of Baguio, Philippines; from Monty Leventhal OAM of Sydney. Australia.
March 2011 Aurora Photo Gallery
[previous Marches: 2010, 2009, 2008, 2007, 2006, 2005, 2004, 2003, 2002]
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 March 18, 2011 there were 1204 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.
| ||The official U.S. government space weather bureau |
| ||The first place to look for information about sundogs, pillars, rainbows and related phenomena. |
| ||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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