A new type of aurora called “the dunes” discovered by aurora chasers in Finland is helping scientists better understand a mysterious layer of Earth’s atmosphere. The aurora – nighttime light displays in the atmosphere near Earth’s poles – take on various shapes and forms. They often appear as rippling curtains of green, red, or purple light. But in October 2018, amateur auroral photographers in Finland discovered a new auroral form they dubbed “the dunes.”
The dunes appear as thin ribbons of green light in the sky, extending toward the equator for hundreds of kilometers. Most auroral light displays are oriented vertically, like curtains hanging down from the sky, but the dunes are arranged horizontally, like fingers reaching toward the horizon.
This video, shot by Kari Saari, shows the dunes appearing over Savojärvi, southern Finland, in October 2018.
Space physicists at the University of Helsinki worked with citizen scientists who first saw the dunes to determine their altitude and have come up with a theory to explain how they form. They report the discovery and their theory in a new study in AGU Advances.
Read more about this research here:
Read the original research paper detailing the findings here:
Video footage taken by Kari Saari and courtesy of Minna Palmroth.
Music: Lullabye by Density & Time.
Video produced by Lauren Lipuma at AGU.
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