Pulsar vs. Quasar — What's the Difference?

A pulsar (from Pulsating Radio Sources) is a highly magnetized rotating compact star (usually neutron stars but also white dwarfs) that emits beams of electromagnetic radiation out of its magnetic poles. This radiation can be observed only when a beam of emission is pointing toward Earth (similar to the way a lighthouse can be seen only when the light is pointed in the direction of an observer), and is responsible for the pulsed appearance of emission.

A quasar (; also known as a quasi-stellar object, abbreviated QSO) is an extremely luminous active galactic nucleus (AGN), in which a supermassive black hole with mass ranging from millions to billions of times the mass of the Sun is surrounded by a gaseous accretion disk. As gas in the disk falls towards the black hole, energy is released in the form of electromagnetic radiation, which can be observed across the electromagnetic spectrum.

Any of several celestial objects emitting periodic, short, intense bursts of radio, x-ray, or visible electromagnetic radiation, generally believed to be quickly rotating neutron stars.

A compact, extremely bright celestial object whose power output can be hundreds to several thousand times that of the entire Milky Way galaxy. Quasars are among the most distant objects in the universe and are generally considered to be a form of active galactic nucleus.

(astronomy) A rotating neutron star that emits radio pulses periodically.

(galaxy) An extragalactic object, starlike in appearance, that is among the most luminous and (putatively) the most distant objects in the universe.

A degenerate neutron star; small and extremely dense; rotates very fast and emits regular pulses of polarized radiation

A starlike object that may send out radio waves and other forms of energy; large red shifts imply enormous recession velocities