The series' first hour, "Origins: Earth is Born," gives viewers a spectacular glimpse of the tumultuous first billion years of Planet Earth-a time of continuous catastrophe. Vivid animation lets viewers witness the traumatic birth of the moon from a titanic collision between Earth and an object believed to have been the size of Mars. Bombarded by meteors and comets, rocked by massive volcanic eruptions, and scoured by hot acid rain, the early Earth seems a highly improbable place for life to have taken root. Despite such violent beginnings, scientists have found new clues that life-giving water and oxygen appeared on our planet much earlier than previously thought.