The Crab Nebula (also known as M1 or NGC 1952) lies approximately 6,500 light-years from Earth in the constellation Taurus. It’s the remains of a great dead star. In place of the old star is a very dense and energetic pulsar that spins rapidly. The large amount of X-rays emitted by pulsars is so stable that astronomers use it to calibrate space instruments. Moreover, it is a “cosmic generator” producing energy rapidly at a rate equivalent to 100,000 suns! Light from the explosion that gave rise to the first nebula reached Earth in 1054 and was recorded by a number of astronomers from different parts of the world, but it took 700 years for the shock waves to settle. dissipate, before the various people can detect the nebula left behind. Finally, the Crab Nebula spans 15 light years!
At the center of the Crab Nebula are two faint stars, one of which is the ancestor of the other (i.e. the star that gave birth to the other). Thanks to this star, M1 is a powerful transmitter of radio waves, X-rays and gamma rays. A remnant of supernova SN 1054, widely observed on Earth in 1054, the star was discovered in 1968 and has since been considered a radio pulsar.
http://360.thuvienvatly.com/images/2016/02/crab.jpg
Source: http://www.fromquarkstoquasars.com/apod-crab-nebula/
