"During this past weekend's strong G3-class geomagnetic storm, low-latitude #auroras spread as far south as #Texas and #Arizona. Upon further review, most of those lights were not auroras at all. Everything #red in this montage is an 'SAR arc'.
"'On Nov. 5th, the ring current was pumped up by hours of strong geomagnetic storming, with energy dissipating into these SAR arcs,' says Jeff Baumgardner of Boston University's Center for Space Physics. 'It was a global event. Our cameras registered #SAR arc activity from #Italy to #NewZealand.'
"Recent research has linked SAR arcs to another phenomenon that is not an aurora: #STEVE. The #mauve ribbon in the sky was not originally thought to have anything to do with Earth's ring current. Yet in 2015, observers in New Zealand caught a bright red SAR arc transforming itself into STEVE like a caterpillar into a butterfly.
"On Nov. 5th, Mark Savage may have witnessed the same metamorphosis over Northumberland, #UK:
"Visible to the naked eye, STEVE materialized from an overhanging red arc. 'The entire process took about 10 minutes,' says Savage. This timescale roughly matches that of another SAR-to-STEVE transition observed over Canada in April 2022. Clearly, the two phenomena are linked, but researchers aren't sure how.
"'The connection is still elusive,' says Carlos Martinis, a leading researcher in the field at Boston University. 'Sometimes SAR arcs evolve into STEVE--but not always. This is a very active field of research, involving citizen scientists and researchers.'
"Did you see an SAR arc on Nov. 5th? Submit your pictures to Spaceweather.com."