The Lives of Stars

A dark, clear night sky is strewn with stars. At any given time, about 3,000 may be seen with the unaided eye. They are of different brightnesses and colours, and at different distances. The age-old questions of humanity have been: What makes them shine? How far away are they? How long do they live?

The story of our developing understanding of these begins in the first half of the Nineteenth Century, and encompasses not only the greatest advances in physics from those times to the present, but also many of the most significant social and political upheavals of the 20th Century that accompanied them. Our understanding was, to some extent, driven by advances in nuclear physics beginning in the 1930s, which in turn had as its goal the understanding of sources of energy in the Sun and stars, and how they drive their evolution and eventual demise.

This lecture will describe the history of our understanding of the physics of the stars – in particular, what makes them such enormous sources of energy capable of steadily powering a star for millions or billions of years. An outcome of these investigations is an understanding of how the elements necessary for the existence of life were forged in the interiors of stars. Where possible, connections with ‘backyard astronomy’ will be described, and some practical experiments suggested to allow one to appreciate the vast scale on which these exotic processes take place.


Dr. Murray Alexander is a professor of Physics at the University of Winnipeg whose primary area of interest concerns the astrophysics of binary star systems.

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