Nebula (catalogue designations M1, NGC 1952, Taurus A) is a supernova
remnant and pulsar wind nebula in the constellation of Taurus. The nebula
was first observed by John Bevis in 1731, and corresponds to a bright
supernova recorded by Chinese and Arab astronomers in 1054. At X-ray and
gamma-ray energies above 30 KeV, the Crab is generally the strongest
persistent source in the sky, with measured flux extending to above 1012 eV.
Located at a distance of about 6,500 light-years (2 kpc) from Earth, the
nebula has a diameter of 11 ly (3.4 pc) and expands at a rate of about 1,500
kilometers per second.