A ring of illuminated ice crystals encircle an Alaskan moon

Our sun isn't the only object in the sky that can produce spectacular optical effects. Take this photograph taken by Sebastian Saarloos on a cold, starlit Alaskan night. This is what's called a "moondog" — a rainbow-like ring around the moon that's caused by the reflection of moonlight (which is reflected sunlight)… »1/30/13 11:20am1/30/13 11:20am

A detailed view of Betelgeuse on a collision course with a nearby wall of dust

Betelgeuse is one of my favorite objects to look at, partly because of its pure red color, and mostly because my imagination fills in the rest. That bright red star — this shoulder of Orion — is a supergiant that's dozens of times more massive than our Sun, and ready to detonate as a supernova any day now (any day… »1/23/13 11:40am1/23/13 11:40am