SOLAR WIND SPARKS AURORAS: Earth is now fully inside a stream of solar wind flowing from a large coronal hole on the sun. The buffeting action of the stream is causing intermittent auroras around the Arctic Circle--some of them quite bright. "For a few minutes on Dec. 8th the sky exploded over Kiruna, Sweden," reports Mia Stålnacke, who took this picture:
"I was lucky to catch this huge colorful corona as it expanded across the night sky," she says.
This is a broad stream of solar wind and it could take Earth two or three days to cross it. G1-class geomagnetic storms and Arctic auroras are likely from now until Dec. 10th. Monitor the realtime aurora gallery for sightings. Free: Aurora Alerts
GEMINID METEOR SHOWER: Canada's Meteor Orbit Radar (CMOR) is picking up echoes from the constellation Gemini. It's a sign that the annual Geminid meteor shower is underway. The bright pink "hot spot" in this CMOR sky map shows where Geminid meteoroids are hitting the atmosphere:
Geminid meteoroids are gravelly debris from "rock comet" 3200 Phaethon. They hit Earth's atmosphere traveling ~35 km/s (78,000 mph) and typically disintegrate about 80 km (50 miles) above Earth's surface. While many Geminids are faint, bright fireballs are not unusual.
At the moment, visible Geminid meteor rates are no more than a few per hour. Sightings will increase in the nights ahead as Earth plunges deeper into the debris zone of 3200 Phaethon. Forecasters expect peak rates to occur on Dec. 13-14 when observers in both hemispheres could see dozens of Geminids despite the glare of a bright full Moon. The best time to look is during the hours after local midnight. [sky map]
AMAZING SUN HALO: Atmospheric optics expert Les Cowley has seen almost every manifestation of ice in the sky that Nature can produce. He's not easy to impress. On Dec 6th, however, Michael Greenham of Magog, Quebec, photographed a display that impressed even Cowley:
"That is a great one," says Cowley.
"The air temperature was -1 C on a calm December morning," says Greenham. Sunlight hitting ice crystals in the air produced "very vivid sundogs and arcs in the sky."
"This magnificent ice halo display is bristling with rare arcs," says Cowley. "From top downwards we have a circumzenithal arc. Touching that is a bright and rare supralateral arc, often mistaken for the rarer 46 degree halo. Then we have a Parry arc, first recorded in 1820 by the famous Arctic explorer William Edward Parry. Touching the familiar 22 degree halo is a 'gull-wing' shaped upper tangent arc. Radiating outward from the sun at far left and right are very rare helic arcs."
Greenham spotted these halos in his front yard. Cowley knows another place to find them: "To best see halos like this choose a subzero day a few km downwind of a ski slope. Snow blowers make high quality halo forming crystals as well as snow!"
Realtime Space Weather Photo Gallery
STUDENT SPECIAL: Is there a young scientist in your life? For Christmas, you can give them the gift of exploration. For the holiday season only, we're reducing the cost of payload space on Earth to Sky Calculus balloons from $500 to only $299.95. Buy an edge of space gift certificate before Dec. 25th and your student can send an experiment, photo, or keepsake item to the stratosphere, completely supported by an Earth to Sky Calculus launch and recovery team.
This is not only a great Christmas gift, but also a good kickstarter for science fair projects. Experiments will be flown and returned along with video footage, GPS tracking, temperature, pressure, altimetry and radiation data.
To take advantage of the discounted rate, payment must be received before Dec. 25th. However, the flight can take place at any time in the next 12 months. A Skype brainstorming session is included with each certificate. Dr. Tony Phillips and other members of the Earth to Sky team will chat with students to help them craft an experiment that will work in the harsh environment of the stratosphere.
More far out Christmas gifts may be found in the Earth to Sky Store. All proceeds support space weather research.
Realtime Airglow Photo Gallery