This spring has been big for fans of the aurora borealis. Shelby took created this photo of five, 1-min tracked shots blended with an untracked foreground shot the night of March 13/14th in Copper Harbor. It shows a phenomenon I’d never heard of, a Strong Thermal Emission Velocity Enhancement aka STEVE about which Space.com says (in part):
A typical aurora — sometimes called the northern lights or the southern lights, depending on the hemisphere in which it’s located — occurs when charged particles from the sun interact with Earth’s oxygen and nitrogen molecules. This interaction excites the molecules and causes them to glow.
But STEVE, formally known as Strong Thermal Emission Velocity Enhancement, is different. In the Northern Hemisphere, the phenomenon is visible from areas farther south than a typical aurora, and it looks like a ribbon of pink or mauve light. Sometimes, STEVE even has a “picket fence” appearance, with green columns of light passing through the ribbon. Auroras, by contrast, usually are shimmering green ribbons.
…The new study examined satellite data gathered above STEVE events in April 2008 and May 2016. The measurements included information about Earth’s magnetic and electrical fields in the magnetosphere, the region of Earth’s atmosphere where the planet’s magnetic field is stronger than any influence coming from the sun. Then, scientists compared the satellites’ findings with amateur photos of STEVE taken from the ground at the same time.
When STEVE was on display, the study authors realized, energetic electrons were pouring into Earth’s ionosphere, the layer of the planet’s atmosphere where atoms lose electrons due to solar and cosmic radiation. The friction that flood creates heats particles, which creates the pinkish glow, almost like an incandescent light bulb.
Satellite information further revealed how the “picket fence” aspect of STEVE develops. The data revealed waves moving from Earth’s magnetosphere to the ionosphere. In this region, the waves can both energize electrons and move them out of the magnetosphere, creating the picket-fence appearance, which happens simultaneously in the Northern and Southern hemispheres.
Lots more at Space.com.
Lots more northern lights on Michigan in Pictures!