M1: This is gas cloud which is the remnant of a huge star which exploded into a supernova in the year 1054 A.D. The original star, with perhaps ten times the mass of our Sun, remains at the center of this nebula, but it now contains perhaps 1.5 times the mass of our Sun, and has collapsed into a neutron star, with a diameter of ten miles, which rotates on its axis 30 times per second. The outer layer of gas is expanding at a rate of about 3 million miles per hour. It is about 6,500 light years from the Sun.
Copyright Mark de Regt, 2002