As the name implies, nuclear physics is the study of the nuclei which lie at the core of every atom in the world. Over 99.9% of the mass of all the ordinary matter in the universe is found in nuclei. Protons and neutrons (themselves made of quarks) are the building blocks of the nucleus, so a large part of nuclear physics is trying to understand the force that holds protons and neutrons together.

A major motivation for studying the atomic nucleus is simply to gain a fundamental understanding of our world, including its origin and future, as well as its current state. Nuclear physics can explain much of the evolution of the universe in the first minutes and years after the "big bang". It also explains how stars continually work to release virtually all of the useful energy in the world, while at the same time assembling the various elements. Thus today there are many nuclear physicists working in the area of astrophysics, including some here at Western.

Some of the conditions in the early universe and in various kinds of stars can be recreated today in large particle accelerators, so scientists who perform experiments have to compete for beam time and often travel to such facilities. Theoretical nuclear physicists use powerful computers to do simulations and calculate predictions which can be compared with experimental results. There are many potential applications of nuclear physics, in energy production, medical diagnosis and treatments, to name a few. It remains an interesting and active field of research in physics.