A vaguely crab-shaped supernova remnant in the constellation of Taurus. Also known as M1 or NGC 1952. 6000 light years distant, it was first identified by Charles Messier in 1758. He was looking for comets at the time. When the nebula didn't move like a comet, he made it the first entry in his now famous list of stationary fuzzy objects that could be mistaken for comets. This list is now known as the Messier Catalog, hence the Crab's M1 designation.
Light from the supernova reached the Earth's neighborhood around July 4, 1054. Its appearance in the sky was noted by Chinese astronomers. At its height, it was bright enough to be visible during the daytime.
The nebula is expanding at 1000 km/s. It is growing at such a rate that changes can be noted from photographs taken in the early 1900s.
At the nebula's center is a pulsar, a rapidly spinning neutron star rotating at 30 times a second. It was one of the first pulsars discovered, first detected in 1969.