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'METEOR SMOKE' LINKED TO NOCTILUCENT CLOUDS: A key ingredient of Earth's strangest clouds does not come from Earth. New data from NASA's AIM spacecraft shows that "meteor smoke" is essential to the formation of noctilucent clouds. [full story] [video]
FIRST AURORAS OF THE SEASON: After a long summer of midnight suns and starless nights, the Arctic Circle is glowing with its first auroras of the new season. Todd Salat photographed the kick-off in Fairbanks, Alaska, on August 6th:
"From 1 am to 1:30 am local time I took these photos of the northern lights dancing above the Fairbanks city lights," says Salat. "Although the nights still do not get completely dark in the far northern latitudes, the deep blue twilight skies proved dark enough to make the auroras stand out. And at a balmy 55° F, it was quite a treat to be watching the lights in t-shirt weather."
The second auroras of the season could appear tonight. NOAA forecasters estimate a 30% chance of polar geomagnetic storms in response to the expected glancng blow from an incoming CME. Aurora alerts: text, phone.
Realtime Aurora Photo Gallery
THE OPPOSITION EFFECT ON MARS: Among the many striking images of Curiosity's August 5th descent to Mars, this one is particularly nerd-tastic because it illustrates an obscure bit of physics often seen on dusty alien worlds. Look inside the circle, then scroll down for an explanation of the bright spot:
"This picture was taken by Mars Descent Imager (MARDI) onboard Curiosity during its final stage of descent towards the surface of the Red Planet," says SWx-reader Radek Grochowski who noticed the optical phenomenon. "Above the falling heat shield you can see a distinct bright spot - an opposition effect."
The opposition effect occurs when sunlight is backscattered from a loosely-packed surface of dust or sand. Particles hide their own shadows, resulting in a bright spot on the ground as seen from above. This phenomenon has been observed on Earth, the Moon, Mars, and even in the rings of Saturn.
Realtime Space Weather Photo Gallery
Realtime Meteor 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 8, 2012 there were 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 |