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SUNDIVING COMET MOVIE: A new video from NASA shows the sundiving comet of July 5th interacting with the sun's atmosphere as it evaporates above the stellar surface. Click here for action.
BIG SUNSPOTS: After more than a week of quiet, solar activity is picking up. NASA's Solar Dynamics Observatory is monitoring two big sunspot groups now emerging over the sun's eastern limb. Click on the image to view a 40-hour movie:
The leading sunspot group, AR1260, is crackling with M- and C-class solar flares among a quartet of Earth-sized cores. Not far behind, sunspot AR1261 is larger and may harbor energy for flares of its own. At the moment, these two sunspot groups are too far off disk-center to affect Earth, but this will change in the days ahead. Readers with solar telescopes are encouraged to monitor developments.
more images: from Pavol Rapavy of Observatory Rimavska Sobota, Slovakia; from Steve Wainwright of Gower S.Wales UK; from John Stetson of Falmouth, Maine; from Rogerio Marcon of Campinas SP Brasil; from Cai-Uso Wohler of Bispingen, Germany
NOCTILUCENT CLOUDS: "The morning of July 26th was electric blue!" says Heiko Ulbricht of Freital, Saxony, Germany. "I woke up at 3 clock, looked out my bedroom window to the north and saw a stunning display of noctilucent clouds." Moments later, he dashed outside with a camera to record the view:
July has been an odd time for noctilucent clouds (NLCs). The month began with an extravagant display that stretched as far south as Colorado and Kansas--odd because NLCs are usually confined to higher latitudes. The event seemed to herald a period of widespread sightings. Observers were disappointed, though, when the clouds quickly retreated to their usual northern habitat. Could this German apparition signal renewed activity? Sky watchers at all latitudes should be alert for electric-blue ripples around sunrise and sunset. Observing tips may be found in the gallery.
more images: from Timo Newton-Syms of Helsinki, Finland
2011 Noctilucent Cloud Gallery
[previous years: 2003, 2004, 2005, 2006, 2007, 2008, 2009]
June 2011 Aurora Gallery
[Aurora alerts: text, voice] [previous Junes: 2010, 2008, 2001]
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 July 27, 2011 there were 1237 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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