That's the big picture. But what shapes the finer detail of the classic auroral patterns—the curtains, folds, and rays—still awaits explanation. Head reeling with ideas from space physics ...

An aurora — also known as the Northern Lights ... comprises dynamic patterns of brilliant light that appear as curtains, rays, spirals, or dynamic flickers covering much of the sky.

On Feb. 22, while near the city of Tromsø, Norway, the aurora suddenly brightened and split into multiple rayed curtains that rose ... brilliant green and pink rays. Everyone on deck screamed ...