The MS lifetime for a star like the Sun is 10 billion years. As efficient as are nuclear reactions, however, stars have only a finite supply of fuel. The most important of these is an enormous inflation of their outer envelopes, which produces the red giants. The diagram at the right shows evolutionary tracks in the HRD for stars of different initial masses. Note that stars like the Sun become much more luminous as evolution proceeds.
More massive stars undergo the whole process much more rapidly than lower mass stars.
It contains star clusters, nebulae, and galaxies. The web site listed below and Norton's contain lists and descriptions of the Messier objects. Starbirth begins when interstellar clouds begin to collapse under their own gravity. Most of this process is hidden from easy view at optical wavelengths by the dust and can only be observed with infrared telescopes. However, once stars form, they disrupt the surrounding clouds, blowing away the gas and dust and often causing it to glow by virtue of ionization from hot stars.