For the next week "we" will look at one of the most fundamental questions about a star:

How does a star produce all the energy that it radiates away into space?

The answer to this explains the existence of the main sequence in the H-R Diagram and leads into the next big topic - the formation and evolution of stars.

One Possible Energy Source:   Coal or Wood burning

Another Possible Energy Source:   Gravitational Potential Energy

The answer had to await some advances in physics and the discovery of Nuclear Energy