Northern Lights out Thursday in the wake of huge solar flares

The aurora borealis are out tonight across a wide swath of the northern U.S.—including sections of the Chicago metropolitan area—in the wake of a giant solar flare which occurred 9 p.m. Tuesday evening, Dec. 12.
Astronomer Dan Joyce tells us the powerful X-Class flare is one of four which have occurred on the sun in the past week, sending the charged particles responsible for initiating this evening’s multi-colored auroral displays streaming toward Earth. These charged particles excite oxygen and nitrogen in the atmosphere, creating the aurora borealis or northern lights. The auroral oval—a swath of the Northern Hemisphere most prone to northern lights—expands southward by a wide margin when strong solar flares initate what space scientists refer to as a geomagnetic storm, which can interrupt certain radio communications and interfere with satellite operation while at the same time prompting aurora displays. Reports in as of 7:40 p.m. Thursday evening indicate northern lights have already been spotted from North Dakota east to Pennsylvania, New York, Vermont and New Hampshire.
It’s most unusual for such strong solar flares to be occurring at this stage of the 11-year solar cycle, says Dan Joyce. We are just two months from the February minimum of the current cycle, a period in which solar flares—especially ones on the scale of the past four this week—are not what scientists expect to see.
Our thanks to Larry Spencer of Crest Hill for the above photograph of green-hued northern lights taken just after 7 p.m. Thursday evening, Dec. 14.
For more information on northern lights, here are some previous blog entries on the subject:
A Weather Kahnnections article by Steve Kahn
Archived photos: Article 1 | Article 2 | Article 3
–By Tom Skilling, WGN-TV Chief Meteorologist

Mercury transits the sun Wednesday—one of only 14 such transits this century

Our astronomer Dan Joyce of Triton College shares this stunning photo of Mercury’s rare transit of the sun which was visible from Chicago beginning 1:12 p.m. Wednesday. The photo was take by one of Dan’s former students Dr. Donald C. Parker who live in Coral Gables, Florida—which is where this photo was taken.
PHOTO COURTESY: Dr. Donald C. Parker, Coral Gables, Florida