Pulsars

As mentioned in the last post, pulsars are a specific type of neutron stars. Neutron stars have very strong magnetic fields, that are not necessarily lined up with their axes of rotation. Pulsars give off radiation as energy is directed along the axis of the magnetic poles and "beamed" towards Earth. These beams or jets are very energetic and can be seen for thousand of light years. When the jet of energy is pointed in the direction of Earth, we see them as a pulsar.

A very badly drawn schematic of a pulsar

A pulsar acts kind of a like a lighthouse in that the beam sweeps around as the light source rotates. Unlike a lighthouse, however, a pulsar's period can be extremely short, on the scale of milliseconds. The faster pulsar discovered has a period of about 3 milliseconds, and for something as large as a neutron star (about 10 km in diameter), the pulsar has to be rotating very fast.

We are unsure whether or not all neutron stars are pulsars, though we do know that most pulsars are neutron stars. Since pulsars can only be detected if the jet of energy is pointed directly towards Earth, we don't know if all neutron stars do this.