Little is known about pulsars, or PULSating stARS. What premier physisists theorize is that pulsar is basically a neutron star (if you don't know what that is you'll have to ask) that gives of electromagnetic radiation (this includes light, visible or not) in a peculiar way. What happens is that a pulsar gives off energy in flashes from varying points of view instead of being able to see it from just any angle, like our sun and other normal stars. The promenient theory is that the pulsar is rotating violently and is giving off channeled electromagnetic radiation in a couple of points, a beam of light if you will. And from a fixed point you will only see it if a beam of energy is pointing of your direction.

A pulsar is the core of a star that has exploded. The Crab Nebula has a pulsar in its center, PSR 0531+21, that spins 30 times per second. It was witnessed as a supernova by Chinese and Arabian astronomers in 1054, and was reported to be as bright as the planet Venus. Its pulsar emits radiation across the electromagnetic spectrum. Pulsars are essentially enormous atomic nuclei, a kind of star called a neutron star. The pulses are caused by a phenomenon called synchrotron radiation. The pulsar is surrounded by plasma, and as the pulsar rotates, its magnetic field and the plasma interact and cause highly directional beams of electromagnetic radiation to form. One way to think of it is like a lighthouse, or the blue and white lights an airport light tower, but spinning very fast (PSR 0531+21 spins at a rate of 30 revolutions per second). Over 700 pulsars have been observed since they were first discovered in 1967. There are probably many more pulsars than we can detect as such, since it is a matter of luck that we find ourselves in the path of a pulsar's beams. Interestingly, the regularity of pulsars was so surprising and seemed so unnatural, the phenomenon was considered early on by some to be evidence of extraterrestrial space-faring beings! The pulsars were thought to be their navigational beacons, similar to our lighthouses, and airport beacon lights. Aboard the Voyager and Pioneer space probes, our location is referenced on a plaque by our solar system's relation in space to 14 pulsars, and the periods and distances of each is given. Whoever finds one of these crafts will, if they know of pulsars, be able to find us, no problem!

A pulsar is the collapsed core of former giant stars. A pulsar is a rapidly spinning neutron star that emit bursts of radiation with telltale regularity. This is where it gets its name. The pulsing star actually doesn't physically pulse. The pulse is a burst of radio waves, the result of the neutron stars rapid rotation and intense magnetic field. They are as heavy as a star, but no larger than a city. Over 600 have been discovered since 1967. Factoid #3- A pulsar can orbit another pulsar. These are known as binary pulsars. Only 50 have been discovered since their dicovery in 1974.

Pulsars are highly magnetized rotating neutron stars that emit a beam of electromagnetic radiation in the form of radio waves. Their observed periods range from 1.4 ms to 8.5 s. The radiation can only be observed when the beam of emission is pointing towards the Earth. This is called the lighthouse effect and gives rise to the pulsed nature that gives pulsars their name. Because neutron stars are very dense objects, the rotation period and thus the interval between observed pulses are very regular. For some pulsars, the regularity of pulsation is as precise as an atomic clock. Pulsars are known to have planets orbiting them, as in the case of PSR B1257+12. Werner Becker of the Max-Planck-Institut für extraterrestrische Physik said in 2006, "The theory of how pulsars emit their radiation is still in its infancy, even after nearly forty years of work."   http://en.wikipedia.org/wiki/Pulsar   Also, here is a great image, http://media-2.web.britannica.com/eb-media/39/21239-004-3DCC5887.jpg The pulsar is the star to the left of the nebula.