Crab nebula. Coloured Chandra X-ray telescope image of the Crab nebula (M1) supernova remnant. At the centre of the innermost ring is a pulsar, a spinning neutron star emitting pulses of radiation 30 times a second. The bright rings are composed of high-energy particles spiralling along magnetic field lines around the pulsar. Jets are escaping from the pulsar perpendicular to the plane of the rings (best seen at lower left). The Crab nebula is the remains of a star which exploded in 1054 AD, an event witnessed by Chinese astronomers. It lies around 6000 light years away in the constellation Taurus. Image made by the Advanced CCD Imaging Spectrometer (ACIS) in 1999.