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ELECTRON WARNING: Analysts at the GSFC Space Weather Lab report elevated levels of energetic electrons around Earth. ("GOES 13 > 0.8 MeV integral electron flux is above 105 pfu." ) This is caused by the high-speed solar stream now blowing around our planet. Spacecraft with orbits passing through or in the vicinity of the Earth's outer radiation belt could be affected by these charged particles.
COLORFUL SOUTHERN LIGHTS: Oh to be in Antarctica. The skies over the polar continent have filled with colorful lights in response to a solar wind stream now buffeting Earth's magnetic field. J. Dana Hrubes sends this snapshot from the Amundsen-Scott research station at the geographic South Pole:
"The auroras last night were just amazing--some of the best we've seen this winter," says Hrubes. The frosty scaffolding in the image is attached to the South Pole Telescope (SPoT), a millimeter wave radio telescope used to study the early evolution of the Universe. Hrubes operates SPoT during Antarctica's winter months. "It's a little cold," he allows, "but the view is out of this world."
High-latitude sky watchers should remain alert for auroras as the solar wind continues to blow.
LAST RE-ENTRY: On July 21st, the crew of the International Space Station photographed an event that will never be repeated: the re-entry of a space shuttle. Marking the end of NASA's 30-year shuttle program, Atlantis dove Earthward in a fiery arc that only six lucky space travelers could see from above:
The green band of light in the background is called "airglow." Airglow is a luminous bubble that surounds our entire planet, decorating the top of the atmosphere with aurora-like color. Although airglow resembles the aurora borealis, its underlying physics is different. Airglow is caused by an assortment of chemical reactions in the upper atmosphere driven mainly by solar ultraviolet radiation; auroras, on the other hand, are prompted by gusts of solar wind.
More pictures from the last flight of Atlantis may be found here.
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 23, 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 |
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| 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 |
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