Starship Asterisk*

Now that several people on this forum have agreed with my earlier explanation , I'm going to disagree with myself :) Looking more at the extra photos linked from the APOD page, the "fan" section looks too crisp and orderly to be just the result of dispersed orientations of the crystals hig...

I'm no expert, but here's my guess: Light pillars happen when light from the source is reflected down (or up) off the flat surface of "plate-shaped" ice crystals to the observer. They only happen when the crystals are oriented mostly horizontally, and that happens when they're falling in c...