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.
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SUNSPOT BREAKTHROUGH: A new breakthrough in sunspot detection could provide days of extra early warning of solar storms heading for Earth. Get the full story from Science@NASA.
AURORA SEASON BEGINS: For the past five nights in a row, sky watchers around the Arctic Circle have witnessed green luminous tendrils dancing across the waning twilight of summer. It's safe to say: Aurora season has begun. Here is the view from Arjeplog, Sweden, just after midnight on August 27th:
"The sky cleared up at midnight and I went out to have a quick look for Northern Lights," says photographer Nenne Åman. "The sky turned green just as I reached the shores of Lake Hornavan--perfect timing. This was my first aurora this season, so I am very happy at the moment!"
The display could intensify this weekend when a solar wind stream is expected to reach Earth. High-latitude sky watchers should be on the lookout for first auroras. Aurora alerts: text, voice.
UPDATED: August 2011 Aurora Gallery
[previous Augusts: 2010, 2009, 2008, 2007, 2006, 2005, 2004, 2003, 2002]
SUNSPOT MOVIE: Sunspots are planet-sized islands of magnetism floating in a fiery sea of solar plasma. Unlike the hard-rocky islands of Earth, however, the "firmament" of sunspots is in a constant state of flux. Boiling motions in the underlying plasma cause sunspot magnetic fields to move and shift, so that the active regions change shape on a daily basis. This movie from the Solar Dynamics Observatory shows the process at work in sunspot AR1271:
Readers, you can witness these changes with your own eyes using a safe sunspot telescope. Several new active regions are popping up across the solar disk, so there should be plenty of targets for sight-seeing this weekend.
more images: from Francois Rouviere of Mougins, France; from John Chumack of Dayton, Ohio; from Steve Wainwright of Gower S.Wales UK; from Pawel Warchal of Cracow, Poland
2011 Noctilucent Cloud Gallery
[previous years: 2003, 2004, 2005, 2006, 2007, 2008, 2009]
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 August 27, 2011 there were 1241 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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