AURORA ALERTS: Did you miss the Northern Lights? Next time get a wake-up call from Space Weather PHONE

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 360^o 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]