On the 4th of July in the year AD 1054, a bright star suddenly appeared in the eastern predawn sky. It was off in the direction of the constellation Taurus, just behind the forward horn tip of the bull. For the next several weeks this new star, this “nova,” was so bright that it could even be seen after sunrise, in the daytime! And then as summer drew to a close, the star faded out of sight and was seen no more. In the western world there is apparently no written record of this star’s appearance: either no one was looking up then, or more likely, the skies were overcast throughout the star’s appearance. But in the east, Chinese astronomers made note of this “guest star,” as they called it, and that’s how we know about it today. If you’re out before sunrise this month, aim your telescope at that part of space behind the forward horn tip of Taurus, and you’ll find the Crab nebula, the exploded remains of a supernova - cosmic fireworks from nearly a thousand years ago.