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.
STORM IN PROGRESS: A major geomagnetic
storm is in progress following the impact of a CME
on August 5th around 1800 UT. Sky watchers at all
latitudes should be alert for auroras after nightfall.
Tip: the best hours for aurora sightings are usually
around local midnight. Aurora
Analysts at the Goddard Space Weather Lab say that
the CME impact may have strongly compressed Earth's
magnetic field, directly exposing satellites in
geosynchronous orbit to solar wind plasma. Stay
tuned for updates on this aspect of the storm.
The arriving CME left the sun on August 4th, propelled
by an M9.3-category
eruption in the magnetic canopy of sunspot 1261.
Click on the image to view a movie of the expanding
cloud recorded by the Solar and Heliospheric Observatory:
Note: The many speckles in this movie
are caused by energetic solar protons hitting the
2011 Aurora Gallery
[previous Julys: 2010,
SOLAR RADIO BURST: The M9-class
solar flare of August 4th produced a burst of shortwave
static so powerful that receivers on Earth picked
it up after sunset. "A RadioJove
observer in Florida recorded the burst when the
sun was 38 degrees below the horizon," reports
amateur radio astronomer Thomas Ashcraft. Ashcraft's
own radio telescope in New Mexico recorded the event
1 hour and 54 minutes after sunset:
"To my knowledge, receptions like this are
very rare," says Ashcraft.
Indeed they are. This event brings to mind the
iconic night-time solar radio burst of March 8,
1958. Five radio telescopes at the University of
Florida picked up emissions from the sun while observing
the planet Jupiter in tthe middle of the night.
On the other side of the world, radio astronomers
in daylit Australia confirmed that a powerful solar
radio burst had taken place at that exact time.
The event is described in a 1959
Nature paper by pioneering radio astronomers
Alex Smith and Tom Carr. They considered the possibility
that solar radio waves might have been reflected
by the Moon or carried to the night side of Earth
by ionospheric ducting. In tthe end, they could
not conclusively explain what happened and to this
day night-time solar radio bursts remain a puzzle.
Noctilucent Cloud Gallery
[previous years: 2003,
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.
August 5, 2011 there were 1241
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
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