INCREASING CME ACTIVITY: During the past 24 hours, the sun has produced at least two coronal mass ejections: movie. One of them, hurled into space by an erupting magnetic filament, could sideswipe Earth on April 30th. Stay tuned for updates. Aurora alerts: SMS Text.
AURORA 'DUNES' SIGHTED OVER CANADA: Auroras still have the capacity to surprise. On April 16th, Matthew Wheeler, an experienced aurora-watcher in Robson Valley, British Columbia, saw a green glow forming in the north--then he noticed something odd. "Horizontal lines caught my attention," he says. "There appeared to be ripples in the aurora."
This video captures 20 minutes of their dynamics:
These are "dunes," a newly recognized form of aurora named after their resemblence to desert sand dunes.
A team of researchers first explained them in a paper published just last year. Dunes are a "mesospheric bore"--a type of atmospheric gravity wave that springs up from Earth's surface and gets caught in a thermal waveguide ~100 km high. When solar wind particles rain down on the bore, they illuminate its rippling structure.
Sky watchers in the Arctic have been seeing dunes for years without understanding what they were. A breakthrough came on Oct. 7, 2018, when multiple groups photographed dunes from widely separated locations in Finland. Triangulation revealed the dunes to be ~100 km high with a pure, monochromatic wavelength of about 45 km.
This is a new field of study with potential for discovery. Monitoring aurora dunes may reveal previously hidden waves and waveguides at the boundary between Earth and space. Have you seen a dune? Submit your photos here.
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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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