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. 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.