Another powerful aurora borealis painted the skies over the Flathead Valley in the third week of November; its shimmering, iridescent colors readily visible to the unaided eye.
Strong auroras have become more common in the past year or so, as the sun experiences the most energetic phase of its roughly 11-year solar cycle. At the height of the cycle, known as solar maximum, the sun’s magnetic poles flip, producing eruptions of electronically charged particles, or ions. These ejected ions hurtle through space and collide with our planet’s magnetosphere and upper atmosphere, and some of the energy released is emitted as visible light absorbed by Earthling eyes on the ground.
Greens and reds are produced by ionic interactions with oxygen at different levels of the atmosphere, while collisions with nitrogen molecules glows blue. Strong solar storms can and have caused communication and power grid blackouts.
More intense auroras are anticipated in the months ahead.
For more images, see the full gallery here
