A pulsar is a neutron star with a very strong magnetic field. Neutron stars are the remnants of massive stars which have reached the end of their lives. These stars have an initial mass greater than 10 times the mass of the sun. Throughout the star's life, hydrogen burns into helium through nuclear fusion. Once enough helium has formed and the pressure is high enough in the star's center, the helium fuses into carbon and oxygen. This process of lighter elements fusing into heavier elements continues until an iron core is formed. Iron has the largest binding energy of all the elements, and hence it cannot fuse into any heavier element. Thus iron simply accumulates under the weight of shells of successively lighter elements which continue to burn. NB ( The homeland of iron is the nova , to this fact the holy Quran refers ; in a holy verse Allah says " we sent down Iron. " Iron , contrary to what people believed is formed in nova" When the iron core can no longer support its own weight and the weight of the rest of the star, it collapses. Within milliseconds, gravity
overwhelms the pressure of the remaining material and a full collapse ensues. In this collapse, protons and electrons combine to make neutrons. The energy released is emitted outward and explosively blows away the remaining material of the star. This material glows and is visible as a supernova remnant. The core of the star is left as a neutron star.
The initial magnetic field of the star intensifies during the collapse. Hence, neutron stars can have very strong magnetic fields , they have very intense magnetic fields, about 1,000,000,000,000 times stronger than Earth's own field.
The magnetic field on Earth, which makes compasses point north, is a trillion (1,000,000,000,000) times weaker than the typical neutron star magnetic field. Neutron stars can "pulse" because of electrons accelerated near the magnetic poles. These electrons travel outward from the neutron star. They emit x-rays and gamma rays when they must travel faster than the speed of light to continue rotating with the magnetic field.
The combination of this strong magnetic field and the rapid rotation of the neutron star produces extremely powerful electric fields, with electric potential in excess of 1,000,000,000,000 volts. An external observers sees a pulse of radiation whenever the magnetic pole is visible. The pulses come at the same rate as the rotation of the neutron star (30 times a second for the Crab pulsar), and are very regular.
