Difference in Evolution
Life of Stars:
The primordial matter generated from the big bang resulted in the formation of hydrogen rich clouds, which collapsed under their own gravitational pull. This process continued until the temperature and pressure inside the core of the clouds become high enough to start a nuclear fusion reaction, and thus stars were born. The hydrogen will fuse into helium, the process continues until the star runs out of the hydrogen and then it will begin burning the helium. Eventually the star will bloat to red giant stage. Depending upon its initial size it will eventually become a white dwarf ,and finally cool to a black dwarf, or become a supernova, which finally ends up either as a neutron star or a black hole. The image above shows a star cluster which resides outside of the Milky Way galaxy.
Life of Quasars:
Based on the studies conducted, scientists now believe that quasars are nuclei of distant active galaxies. Many of the galaxies are believed to have a central massive black hole, which attracts matter into it. This matter forms an accretion disk around these black holes. Due to frictional heating from collisions these particles have as they rotate about the black hole, they will reach extremely high temperatures. so high that the nuclei of these galaxies out-shine all of the rest of the stars in that galaxy. Besides that, as the matter is devoured by these black holes, enormous amount of energy will be released by the matter falling into the black hole, which then radiates as cosmic jets along the south and north poles of these black holes.
An alternative theory is that quasars are actually part of some new type of galaxy. As we are not completely aware of the processes which occur during the formation of a galaxy, some scientists believe that these quasars may be the initial stage of galaxy formation. In 1959 the first quasar was detected, which is named – 3C 273, in the constellation Virgo. In 1963, T. Matthews and A. Sandage detected a large redshift in the spectrum of 3C 273, indicating that the object was possibly a distant galaxy. The image above shows a quasar.