Neutron_stars arise at the end of the development of a star. They are formed from the remains of the core after a supernova. Pulsars are rotating neutron stars that emit radiation impulses at regular intervals. They were discovered by radio_telescopes.
In 1967 an astrophysicist named Jocelyn Bell discovered distant radio impulses that were repeated at regular intervals of 1.3 seconds. Austrian physicists (Thirring and Lense) had discussed this phenomenon since 1918, and had posed the question whether space itself would be influenced near such a rotating neutron star. The discovery of pulsars also proved the existence of neutron stars.
Neutron stars are about 10 kilometers in diameter. They are made up of a solid core surrounded by several neutron rich layers. They have a very high density. One teaspoonful of this star's mass would weigh a billion tons!
Neutron stars are called pulsars if they spin rapidly and emit two streams of radio_waves. These streams are radiated from their north and south poles respectively. It is thought that this concentrated radiation is associated with the rapid rotation of the magnetic_field.
One example of a pulsar can be observed as a bright object in the center of the Crab_nebula. This pulsar rotates about its own axis about 30 times per second.
The speed of rotation of all pulsars decreases over time. Ultimately, they disappear completely.
