Astronomy explores the universe beyond the earth and attempts to understand the physical processes that describe its contents. Essentially all civilizations have developed astronomy to some degree, with records extending back to the Babylonians. The modern development of astronomy began with Galileo turning a telescope to the sky and the heliocentric model of the solar system. Astronomy and astrophysics have undergone a revolution in the past fifty years as telescopes ranging from the radio to the gamma ray have discovered the relict radiation from the Big Bang, stars and galaxies that were forming not long after, ultradense neutron stars and black holes, as well as planets around other stars. Astronomy as a discipline is a distinctive integration of many of the sciences. At the introductory level it is used to provide a non-technical overview of the scientific approach to questions and our current understanding. At the more advanced level a quantitative physical understanding of astrophysical systems is developed. A graduate in astronomy has a wide grounding in modern physical science which is important for a wide range of roles in society.