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ANOTHER X-FLARE--ALMOST: Fast-growing sunspot complex 1161-1162 erupted on Feb. 18th, producing an M6.6-class solar flare. The almost-X category blast was one of the strongest flares in years and continued the week-long trend of high solar activity. NOAA forecasters estimate a 75% chance of more M-flares during the next 24 hours.
WAVES OF IONIZATION: Waves of ionization are rippling through Earth's upper atmosphere in response to the recent onslaught of solar flares. This affects the propagation of radio signals--suppressing some frequencies and boosting others. By monitoring distant transmitters at a frequency of 23.4 kHz, Rudolf Slosiar of Bojnice, Slovakia detected nearly a dozen sudden ionospheric disturbances (SIDs) on Feb. 18th:
"Each surge in signal strength corresponds to a specific solar flare," notes Slosiar. "Individual peaks exactly match events recorded by Earth-orbiting satellites."
More waves of ionization are iin the offing as sunspot complex 1161-1162 continues to crackle with M-class solar flares. The next SID could be over your backyard. Do-it-yourself SID monitors are available from Stanford University.
more SIDS: from Roberto Battaiola of Pantigliate, Milan, ITALY; from Jan Karlovsky of Hlohovec, Slovakia; from Rob Stammes of Laukvik, Norway.
CME SPARKS AURORAS: One and possibly two CMEs hit Earth during the early hours of Feb. 18th, creating a gusty solar wind environment around our planet and fueling a minor G1-class geomagnetic storm. During the storm-peak, auroras were visible over Canada despite interference from the full moon:
"The auroras were very colorful," reports photographer Sylvain Serre from Salluit, an Inuit village in Nunavik, Canada. "It was worth going out in the cold weather (-30 C) to see the show."
Although the storm has subsided, it could flare up again as the solar wind continues to swirl around Earth. High-latitude sky watchers should remain alert for auroras.
February 2011 Aurora Photo Gallery
[previous Februaries: 2010, 2009, 2008, 2007, 2006, 2004, 2003, 2002]
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 19, 2011 there were 1198 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 |