It was the year 1054, and Chinese astronomers were astonished. In the region of sky we can see tonight, there was a brilliant interloper just above Orion. Shining more brightly than Venus, this “guest star” was visible during daylight for 23 days. It was over a year before it faded altogether from the night sky.
Gone, but not forgotten. The zombie corpse of this supernova has survived as a tangled cloud of gas threaded with magnetism, that we call the Crab Nebula. You’ll need a telescope to see it; but if your eyes were sensitive to radio waves or X-rays instead of light, the Crab Nebula would be among the brightest objects in the sky.
