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X-FLARE--ALMOST: Fast-growing active
region 1161 erupted this morning, producing an M6.6-class
solar flare at 1011 UT. The almost-X category blast
was one of the strongest flares in years and continued
the week-long trend of high solar activity. SOHO
coronagraph images show no accompanying CME, so
Earth effects should be minimal.
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.
2011 Aurora Photo Gallery
[previous Februaries: 2010,
PROMINENCE: A gigantic tendril of
hot plasma is whipping and dancing along the sun's
northeastern limb. "Wow, what a monster!"
says amateur astronomer Pete Lawrence, who sends
this picture from his backyard observatory in Selsey
The plasma is barely contained by unstable loops
of magnetism, and the whole structure could fly
off into space later today. If it does erupt, Earth
will not be in the line of fire. This solar activity
is not geoeffective, merely photogenic. Readers
with solar telescopes are encouraged to monitor
more images: from
the Solar Dynamics Observatory in Earth orbit
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
all the time.
February 18, 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.
official U.S. government space weather bureau
first place to look for information about sundogs,
pillars, rainbows and related phenomena.
call it a "Hubble for the sun." SDO
is the most advanced solar observatory ever.
views of the sun from NASA's Solar and Terrestrial
and archival images of the Sun from SOHO.
the NOAA Space Environment Center
underlying science of space weather