Thursday, February 17, 2011
Vreemde halo,s in Finland waargenomen.. ( Spaceweather.com)
They came from outer space--and you can have one! Genuine meteorites are now on sale in the Space Weather Store. They make a unique Valentine's gift.
AURORA WATCH: NOAA has slightly downgraded the chance of geomagnetic activity on Feb. 17th to 35%. Those are still good odds, however, so high-latitude sky watchers should be alert for auroras.
MYSTERIOUS SUN HALOES: Most sun haloes are circles. They surround the sun when sunbeams hit ice crystals in the air. The haloes this week in Finland, however, were not circular. Olli Leivo sends this picture from Lahti in southern Finland:
Photo details: Canon EOS 550D, 50mm, f11, 1/250s. More images: #1, #2, #3, #4
"Finland has had a spate of elliptical halos over the last few days produced by ice crystals precipitating out of low clouds. The ones Leivo photographed are superb," says atmospheric optics expert Les Cowley. "Elliptical halos are rare and we do not understand how they are formed. A popular theory is that hexagonal plate-shaped crystals with very blunt pyramidal ends make them. But ray tracing simulations using these crystals do not reproduce the halo’s fine detail properly. Moreover, these crystals are physically unrealistic because crystal faces follow lines of atoms in the crystal lattice – blunt pyramidal ends do not! The mystery remains."
AMAZING SUNSPOT MOVIE: A week ago, sunspot 1158 didn't exist. Now it is wider than the planet Jupiter and unleashing the strongest solar flares since Dec. 2006. Click on the arrow to witness the amazing 5-day development of this active region, courtesy of NASA's Solar Dynamics Observatory: