ARCTIC DREAM SKY: Auroras are dancing around the Arctic Circle on Feb. 1st as Earth moves deeper into a stream of fast-moving solar wind. Observers in Norway and Sweden are calling the display “the best of the season” and perhaps “the best in years.” Eva Kristiansen sends th[e top] picture from Tromsø.
What a dreamsky!“ says Kristiansen. “We’re seeing strong auroras in all the beautiful colors–a really amazing event.”
This stream of solar wind is flowing from an unusually wide hole in the sun’s atmosphere. It arrived during the late hours of Jan. 31st, and Earth will probably be inside the stream for another 24 to 48 hours. NOAA forecasters say there is a chance of G1-class geomagnetic storms with isolated periods of G2-class storming on Feb. 1st. followed by lesser activity on Feb. 2nd and 3rd.
First contact with the solar wind stream on Jan. 31st produced this “red angel” over Tromsø, Norway. [center] Photo credit: Marianne Bergli.
A SUNDOG FALLS THROUGH A HOLE IN THE CLOUDS: Jan. 28th was a cloudy day in Lynden, Washington. Suddenly, a hole formed in the cloud deck–and a sundog fell through. Ben Ellis was out for a run and photographed the phenomenon with his iPhone [bottom].
What happened? Ellis witnessed a “fallstreak hole.” These can form in high altitude clouds when the temperature drops below 0o C– but water droplets in the cloud do not freeze. They remain in a supercooled liquid state, delicate and unstable. Suddenly, a disturbance occurs; perhaps a plane flies by. The sub-zero water droplets begin to crystallize in a wave expanding outward from the point of the disturbance. Ice crystals billow from the resulting “hole.”
As ice crystals fell from this fallstreak hole, they caught the rays of the nearby sun, forming a rainbow-colored sundog.
radioblueheart reblogged this from merelygifted
merelygifted posted this
