What are pulsars and quasars?
Pulsar is short for Pulsating star while Quasar is short for Quasi-stellar radio source.
Despite their confusingly similar names, these are very different celestial objects.
A pulsar (originally short for ‘pulsating star’) is a rapidly spinning neutron star – the remnant of a supernova explosion. It has a powerful magnetic field, shooting out jets of radiation that sweep across space like lighthouse beams – when they line up with Earth they appear as a rapidly repeating burst of light, radio waves and other radiations.
"The theory of how pulsars emit their radiation is still in its infancy, even after nearly forty years of work. There are many models but no accepted theory".
A quasar (from ‘quasi-stellar radio source’) is, in fact, a distant galaxy with a fluctuating blaze of light and other radiations coming from its central regions. The activity in these galaxies is caused by a giant black hole at their very heart, pulling in material from its surroundings, tearing it to shreds and heating it up to tremendous temperatures before swallowing it up.
Quasars are the brightest objects in our universe, although to see one through a telescope they do not look that bright at all. This is because quasars are so far away. They emit radio waves, x-rays and light waves. Quasars appear as faint red stars to us here on Earth.