The Sky at Night — Episode 10: The Mystery of the Spiral Arm

You are watching the episode The Mystery of the Spiral Arm Why are some galaxies, such as ours, spiral in form like huge Catherine wheels, and why are stars born inside these arms? Patrick Moore and Dr John Beck -man of Queen Mary College talk about the mysteries of spiral galaxies, and how the massive, powerful stars inside the arms affect the whole course of the history of our own galaxy and other systems.