Heaven and Hell

Heaven and Hell is the fourth episode of Cosmos A Personal Voyage. It first aired 19 October 1980 on PBS.

Summary
Carl Sagan discusses comets and asteroids as planetary impactors, giving recent examples of the Tunguska event and a lunar impact described by Canterbury monks in 1178. He gives to a description of the environment of Venus, from the previous fantastic theories of people such as Immanuel Velikovsky to the information gained by the Venera landers, and its implications for Earth's greenhouse effect.

Update
The Cosmos Update highlights the connection to global warming.