The Best Episodes Directed By Alice Harper

"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.

"Origins: How Life Began," zeroes in on the mystery of exactly how it happened. Join the hunt for hardy microbes that flourish in the most unlikely places: inside rocks in a mine shaft two miles down, inside a cave dripping with acid as strong as a car battery's, and in noxious gas bubbles erupting from the Pacific ocean floor. The survival of these tough microorganisms suggests they may be related to the planet's first primitive life forms. Host astrophysicist Neil deGrasse Tyson deepens the search by investigating tantalizing and controversial chemical "signatures" of life inside three-billion-year-old rocks and meteorites found around the world.