iPHONE VS
ANDROID! Actually, it doesn't matter which
phone you carry. Our cool, new app turns both smartphones
into field-tested satellite trackers. Learn
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NASA
MISSION TO TOUCH THE SUN: NASA's daring plan
to visit the sun took a giant leap forward today with the
selection of five key science investigations for the Solar
Probe+ spacecraft. Get the full
story from Science@NASA.
FARSIDE
ACTIVITY CONTINUES: On Sept. 1st at 21:55
UT, NASA's STEREO-A spacecraft has detected a strong solar
flare on the far side of the sun. The blast produced a
flash of extreme UV radiation and hurled a coronal mass
ejection (CME) over the sun's southwestern limb:
See the cloud expand: 0.6
MB gif animation
The cloud is heading in the general direction
of Saturn and poses no threat to Earth. Like a similar
flare reported on Aug. 31st, this event was centered on
old sunspot group 1100. Solar rotation will turn the active
region back toward Earth for possible geoeffective action
in about 7 to 9 days. Stay tuned!
VIRTUAL
REALITY PARHELIC CIRCLE: A parhelic
circle is an unforgettable sight. Thin and pale, it circles
the zenith in a majestic arc, always keeping the same distance
above the horizon. "I've been looking for a parhelic
circle for more than 13 years," says photographer Laurent
Laveder of Pluguffan, France. "Yesterday I finally
saw one." He rushed for his camera and quickly snapped
enough pictures to assemble a complete 360o zenith-to-horizon
composite view of the phenomenon. Click on the image below
to experience the VR
parhelic circle:
Parhelic circles are caused by sunlight reflecting from the
vertical faces of ice crystals--millions of them floating
in thin cirrus clouds spread almost evenly across the wide
blue sky. As Les Cowley notes in his authoritative
web page on the subject, "the parhelic circle appears
simple yet more ray paths contribute to it than in any other
halo. Some are very intricate."
A striking aspect of the parhelic circle is its dual personality.
At the same time it appears both circular and straight. "These
two pictures (1,
2) illustrate
the effect," says Laveder. More images may be found here.
August
2010 Northern Lights Gallery
[previous Augusts: 2009,
2008, 2007,
2006, 2005,
2004, 2003]
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