sentences:  The nebula lies in the Perseus Arm of the Milky Way galaxy, at a distance of about from Earth.It has a diameter of , corresponding to an apparent diameter of some 7 arcminutes, and is expanding at a rate of about , or 0.5% of the speed of light.At the center of the nebula lies the Crab Pulsar, a neutron star across with a spin rate of 30.2 times per second, which emits pulses of radiation from gamma rays to radio waves.