A pulsar is a rapidly spinning neutron star that emits energy in pulses. Like a
black hole, it is an endpoint to stellar
evolution. The "pulses" of high-energy
radiation we see from a pulsar are due
to a misalignment of the neutron star's
rotation axis and its magnetic axis.
Pulsars pulse because the rotation of
the neutron star causes the radiation
generated within the magnetic field to
sweep in and out of our line of sight
with a regular period.
simple in theory, but complex in reality.
They are modeled as spinning magnets.
This simple view hides the enormous
complexity of these interesting objects,
which come in several types.
For type specific information see gamma ray pulsar, x-ray pulsar, anomalous x-ray pulsar, magnetar; for a list of known pulsars, see Category:Pulsars.