The twelfth episode of Cosmos: A Spacetime Odyssey, "The World Set Free," will air tonight on Fox. In "The World Set Free," The Ship of the Imagination travels to our near neighbor Venus, where we begin our journey to discover the long history of global warming and the greenhouse effect. Later, explore the detrimental effects of climate change and trace the magnitude of our impact on the Earth's atmosphere. However, with knowledge, technology and science within our grasp, imagine a hopeful future where we dedicate our efforts to taking care of our home, Planet Earth. The episode is hosted by Neil deGrasse Tyson. Cosmos: A Spacetime Odyssey, "The Immortals," airs Sunday, June 1, 2014 at 9 PM ET on Fox.