Pulsars are rotating neutron stars that emit a beam of electromagnetic radiation that is visible only if you stay in its path. These dead stars got their name because their emission appear to be pulsating in space.
The creation of a pulsar is similar to that of a neutron star. A star, with the mass of 1.4 to 3.2 of our sun finishes its life and explodes as a supernova. During this time, the core of the star is compressed into a very small space, but not small enough to form a black hole. This object is called a neutron star. Because the neutron star is formed with a very high rotation speed, a beam of radiation is emitted along the magnetic axis of the pulsar, which spins along with the neutron star.
There are 4 type of Pulsars: Radio Pulsars, Optical Pulsars, X-ray Pulsars and the rarest type, Gamma Ray pulsars, which are mostly composed of young neutron star with strong magnetic fields.
Gamma Ray pulsars are also the most dangerous type of pulsars for Earth. If a Gamma Ray beam emitted by a Pulsar from as far away as 6.500 light years away would pass through the Solar System, it would cause mass extinction on Earth. The Gamma Ray would deplete our ozone layer, causing acid rains and would initiate a cooling of the Earth. Basically, almost everything would die, and only small bacteria could survive. But the chance of such an event to happen is very small, so we don’t have to worry at the moment.
It is estimated that there are 200.000 Pulsars in the Milky Way.
Thanks for reading!