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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SPACESHIP AT DAWN: The International Space Station is beginning a series of bright morning passes over North America. Check the Simple Satellite Tracker for flyby times, then set your alarm to see a spaceship at dawn. It's a nice way to start the day.
ALMOST QUIET SUN: Solar activity is low, but not zero. This morning a coronal mass ejection billowed away from the sun's northern hemisphere. SOHO (the Solar and Heliospheric Observatory) recorded the blast:
Imagery from NASA's twin STEREO probes reveal the source of the explosion: a magnetic filament on the farside of the sun erupted. The cloud will miss not only Earth but also every other planet as it sails up and out of the plane of the solar system. No auroras are in the offing.
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 25, 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 |
| ||for out-of-this-world printing and graphics |