Once again, the sun has turned its face toward Earth in a particular way — not with destruction, but with color. A coronal hole, a natural opening in the sun's magnetic atmosphere, is streaming charged particles toward our planet, and on Wednesday night those particles will collide with the upper atmosphere over twelve northern states, producing the aurora borealis. It is a reminder, offered only a handful of times each year, that Earth is not a closed system but a participant in something vast and luminous.