Synopsis by Alice Day
The fragility of the Earth is emphasized in this program, as host Tom Selleck reviews the special nature of a planet that is able to support life. He discusses the physical characteristics of Earth in comparison with the other planets of the solar system, and points out the balance that is necessary for life to flourish. This balance is in direct contrast to both the outer and inner planets, which lack water and the temperate conditions and chemical composition required for human life. Earth's water cycle and abundance of plant life are part of its unique environment.