We now understand the stars in almost all their essentials, and only details remain to be worked out. The astrophysical study of the stars provided many crucial insights. The overriding insight is that the Sun is a star, with properties typical of those of billions of other stars in our Galaxy. This recognition resolves thousands of years of religious, philosophical, and scientific debate. Another important insight involves the age of the universe.
Stellar evolution establishes the basic time scale of the universe.
The age-dating of stars and therefore the systems which contain them is one of a handful of methods astronomers have for learning about the history of the universe. The Earth and all its inhabitants are made of atoms which passed through stars now long dead. With a small telescope, you can explore many facets of stellar evolution. In fact, most of the basic evidence on stellar astrophysics was gathered historically with quite modest telescopes. This lecture introduces these subjects.