Beginning with the history of astronomy (Ptolemy, Copernicus, Giordano Bruno, Galileo), this program considers the mathematics of motion (velocity, acceleration); gravity (Kepler’s discoveries, Newton’s laws, center of gravity, astronomical units); the properties of stars (parallax, flux, luminosity, color, Hertzsprung-Russell diagram); relativity (Einstein’s theories, speed of light, space-time); and the large-scale structure of the universe (Big Bang, Cosmological Principle, Hubble’s law). Humankind has come a long way in our understanding of the cosmos—but we’re still only scratching the surface of astrophysics, with discoveries of incalculable value still waiting to be made. A viewable/printable instructor’s guide is available online. A Films for the Humanities & Sciences Production. A part of the series Physics in Action. (31 minutes)