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QUIET SUN: With no strong flares for more than three days, the sun's x-ray output has nearly flatlined. Solar activity is low, and NOAA forecasters put the odds of an X-flare today at less than 1%. Solar flare alerts: text, phone.
CORONAL HOLE: A dark hole in the sun's atmosphere--a "coronal hole"--is turning toward Earth. NASA's Solar Dynamics Observatory captured this image of the gaseous chasm, which measures more than 200,000 km from end to end, during the early hours of August 23rd:
Coronal holes are places where the sun's magnetic field opens up and allows the underlying atmosphere to escape. A stream of solar wind flowing from this coronal hole should reach Earth on August 26-27. High-latitude sky watchers should be alert for auroras on that date. Aurora alerts: text, phone.
Realtime Aurora Photo Gallery
SATELLITE THROWN OVERBOARD: On August 20th, more than 400 km above Earth, Russian cosmonauts spacewalking outside the International Space Station threw a 20-pound metal sphere into orbit. Some reporters have likened the launch to a game of Lacrosse because of the Lacrosse-style basket station commander Gennady Padalka used to propel the satellite overboard.
Last night in Brockville, Ontario, veteran satellite watcher Kevin Fetter video-recorded the "Spherical Satellite" as it passed by the 2nd-magnitude star gamma Cygnus:
"It looked to be between mag 7 and 8--too dim for the naked eye but bright enough to see in binoculars," says Fetter.
The 21-inch-wide satellite will serve as a target in space that Russian scientists will use to test space tracking techniques for monitoring space junk and to study how it re-enters Earth's atmosphere. The ball is expected to stay in orbit for about three months before falling back to Earth.
Realtime Space Weather Photo Gallery
Realtime Noctilucent Cloud Photo Gallery
[previous years: 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2011]
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 23, 2012 there were 1327 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 |