What are quasars, pulsars, and radio waves in space?
Pulsar: Rapidly rotating Neutron star; Quasar: Black Hole; Radio Waves: Electromagnetic Radiation.
A pulsar is a rapidly rotating Neutron Star that emits beams of Electromagnetic Radiation from its poles. A neutron star is the remnant of a star that did not have enough mass to become a black hole (but has a crazy amount of mass - the gravity is so intense that on the surface a marshmallow would explode with the force of an atomic bomb!) but enough mass to not end up as a white dwarf.
The Neutron star is rapidly rotating, and this weirdly bends its magnetic fields to twirl around from the poles (north & south) like spaghetti on a fork. The magnetic fields make Electromagnetic radiation from the star to be concentrated to emit in beams. These beams are like a light house's, turning "on & off" as they rotate towards and away from the observer. They have the predictability of an atomic clock!
Is a black hole turned in a way from the observer so that only the accretion disk, the jets, and radio lobes visible. Note that Quasars are very old because they are very, very, very far away, and are rare now days (they were most common a LONG time ago).
Radio Waves are Electromagnetic Radiation, which, according to Dictionary.com is “radiation consisting of electromagnetic waves, including radio waves, infrared, visible light, ultraviolet, x-rays, and gamma rays.