If you look to the northern sky tonight, you’ll see an array of familiar star patterns, including the Big Dipper and the W-shaped constellation Cassiopeia. But the northern sky also features a constellation that’s so dim that you can’t see it from cities and many suburbs. Yet Camelopardalis, the giraffe, boasts one of the most extraordinary double stars in the galaxy. MY Camelopardalis is about 13,000 light-years away. It consists of two hot blue stars that are tied together by their mutual gravitational pull. Both stars are far bigger and heavier than the Sun. Their most remarkable property, though, is their proximity to each other. Their cores are so close together that they whirl around each other once every 28 hours. Even more remarkable, the outer layers of these two giants are actually touching each other. The two stars eventually will merge to form an even greater star — one of the hottest, brightest, and most massive stars in the galaxy. It won’t last long, though — it’ll blast