Did you sleep through the auroras of Dec. 14th? Next time get a wake-up call: Spaceweather PHONE.
DARK CLOUDS: Four hundred years ago, astronomers thought sunspots might be dark clouds in the sun's atmosphere. Galileo proved otherwise. By tracking the motions of sunspots, he showed that they were not clouds but islands (of magnetism) on the sun's surface. Case closed.
Except for one thing: There are dark clouds in the sun's atmosphere. Eric Roel of Valle de Bravo, Mexico, photographed one yesterday:
Photo details: SolarMax40, 76mm TeleVue, f/6.3.
It's called a filament--a hundred-thousand-mile long cloud of hydrogen held above the sun's surface by magnetic force fields. Filaments existed 400 years ago, but Galileo couldn't see them because he didn't have a filter tuned to the deep-red glow of solar hydrogen.
This filament is moving toward the sun's western horizon, where it will vanish a few days from now. If you have a solar telescope, take a look before it goes. You might see something Galileo never did.
more images: from Emiel Veldhuis and Patricia Cannaerts of Zwolle, the Netherlands and Westerlo, Belgium.
DISORDERLY CORONA: When the sun rose over Taos, New Mexico, on Dec. 26th, onlookers witnessed a beautiful pastel haze announcing the sun behind the clouds. Master goldsmith and amateur photographer Phil Poirier took this picture:
What is it? The best description would be a "disorderly corona," says atmospheric optics expert Les Cowley.
"Colors in the sky like those on oily pools are a sign that tiny water drops in clouds are scattering sunlight," he explains. "We see a corona with circular rings if the drops are the same size all across the cloud. Drop sizes varying from place to place, on the other hand, make chaotic colors--iridescence. The pastel haze in Phil Poirier's picture is an 'in between' case. Call it a disordered corona! Look out for these effects when the sun is just hidden behind a cloud or even a building."
BONUS: December Aurora Gallery
updated Dec. 28, 2006