FARSIDE SUNSPOT: NASA's STEREO-A spacecraft is monitoring an active region on the farside of the sun. Here it is. The probable sunspot will turn to face Earth later this week, ending a string of spotless days. A CME emerged from the region on May 2nd and 3rd, so it really is active. Aurora alerts: SMS Text.
BLACK AURORAS OVER SCOTLAND: Red. Green. Purple. These are the colors we usually see during any display of auroras. On April 18th, Alan C. Tough of Hopeman, Moray, Scotland saw something else. "Black," he says. In the photo below, "note the dark vertical strip above the green band, which is devoid of any normal auroral colour."
Black auroras have been seen before. They are dark rings or black blobs that sometimes appear in an otherwise ordinary expanse of auroral light. Some researchers call them "anti-auroras." The black auroras in Tough's photo are circled here.
Ordinary auroras are caused by electrons raining down from space, hitting Earth's upper atmosphere and making the air glow. Black auroras are the opposite. Instead of electrons raining down, electrons are propelled upward, back into space. This diagram shows what happens:
Europe's fleet of Cluster spacecraft flew in formation over a black aurora on Jan. 14, 2001, and saw the process in action. Sensors onboard the spaceraft detected strong positive electric fields in the black aurora zone. These idiosyncratic fields were stopping, and even reversing, the normal downward rain of aurora-causing electrons.
The study of black auroras is still in its infancy, and forecasters cannot yet predict when or where they might appear. Aurora watchers, the next time a geomagnetic storm erupts, be on the lookout for black. Aurora alerts: SMS Text.
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MOTHER'S DAY IS MAY 9TH: Are you looking for an out-of-this world Mother's Day gift? Consider this: Every time the students of Earth to Sky Calculus launch a cosmic ray balloon, they include something extra in the payload--something Mom will love:
Every item in the Earth to Sky Store has flown to the edge of space and comes with a greeting card showing the item in flight. The interior of the card tells the story of the gift's journey from launch to landing. Mom-satisfaction guaranteed!
Mother's Day Special: Use coupon code "SPACEMOM" at checkout for a 10% discount. Offer valid from now until Mother's Day (May 9, 2021) .
Far Out Gifts: Earth to Sky Store
All sales support hands-on STEM education
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