Learn to photograph Northern Lights like a pro. Sign up for Peter Rosen's Aurora Photo Courses in Abisko National Park. | | | GEOMAGNETIC UNREST: A coronal hole surrounding the sun's south pole is spewing solar wind toward Earth. This could cause geomagnetic unrest and auroras around the Arctic Circle on Feb. 1-3: photos. Aurora alerts: text, voice CLOUDTOP GREEN FLASH: Spaceweather.com reader Mila Zinkova of San Francisco was photographing the sunset on Jan. 29th when a puff of sun detached itself and turned green. It was a rare cloud-top green flash: Atmospheric optics expert Les Cowley explains what happened: "San Francisco and the Californian coast is a world top spot for green flashes. Air is cooled by the cold offshore current and topped by warmer air from inland to provide the ideal temperature profile for sunset mirages and flashes." "Mila's flash might be something extra special - a 'cloud-top' flash. These are seen as the sun's rays graze a distant cloud bank. Marine stratus can be trapped by temperature inversion layers which could generate some of the flashes. But that is not always the case; there is much unexplained about them." Realtime Space Weather Photo Gallery RED AIRGLOW: The OGLE telescope in Las Campanas, Chile, is hunting for signs of Dark Matter in the Milky Way using a technique called "microlensing." This week, to highlight OGLE's mission, astrophotographer Yuri Beletsky lined up his camera behind the observatory dome with the Milky Way in the background. He captured not only the center of the galaxy, but also a fine display of red airglow: "The Milky Way emerged from the top of the dome like a stellar fountain," says Beletsky. "Red airglow is quite prominent in the background." Airglow is aurora-like phenomenon in the upper atmosphere caused by chemical reactions driven mainly by solar ultraviolet radiation. Human eyes seldom notice the faint glow, but It can be photographed on almost any clear dark night, anywhere in the world. The curious thing about Beletsky's photo is not the presence of airglow, but rather its color--red. Airglow is usually green, the color of light from abundant oxygen atoms in a layer 90-100 km high. Red airglow comes from oxygen, too, but in a more rarefied layer of air 150 - 300 km high. Why did red dominate green on the night of Beletsky's photo shoot? The wavy structure of the red glow offers a clue: High-altitude gravity waves might have altered the temperature and density of the upper atmosphere just enough to favor red. Consider it a beautiful mystery. UPDATE: Steve Smith of the Center for Space Physics at Boston University thinks the red color might be caused by OH instead of O. "Yuri Beletsky took a wonderful photo of the Milky Way and airglow," he says. "I don't think that the red airglow is due to O(1D) emission from 250 km. I think its probably due to OH from near 85 km. The Meinel bands extend from ~600nm into the IR and although the visible bands are fainter those in the IR, they are still reasonably bright. Also, the wave structures are also well-defined - that is unusual (but not impossible) in O(1D) emission." Realtime Aurora Photo Gallery Realtime Comet Photo Gallery Every night, a network of NASA all-sky cameras scans the skies above the United States for meteoritic fireballs. Automated software maintained by NASA's Meteoroid Environment Office calculates their orbits, velocity, penetration depth in Earth's atmosphere and many other characteristics. Daily results are presented here on Spaceweather.com. On Feb. 1, 2015, the network reported 1 fireballs. (1 sporadic) In this diagram of the inner solar system, all of the fireball orbits intersect at a single point--Earth. The orbits are color-coded by velocity, from slow (red) to fast (blue). [Larger image] [movies] 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 February 1, 2015 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 | |