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. It moves 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. The Cosmos Update highlights the connection to global warming.
Scientists have started looking to the heavens and wondering what the weather might be like on other planets. Today, we are witnessing the birth of extra-terrestrial meteorology. They began with our solar system, sending spacecraft to explore its furthest reaches, and now the latest telescopes are enabling astronomers to study planets further afield. Our exploration of the universe is revealing alien worlds with gigantic storm systems that encircle entire planets, supersonic winds and extreme temperatures. On some planets, temperatures are so hot that the clouds and rain are believed to be made of liquid lava droplets, and on other planets it is thought to rain precious stones. We thought we had extreme weather on Earth, but it turns out that it is nothing compared to what's out there.
Europa - an icy moon of Jupiter 485 million miles away from Earth - may be our best hope for finding alien life in our solar system. Everywhere we find water on Earth, we find life. What does this mean for the search for life beyond Earth? Scientists believe that on Europa there is a liquid ocean buried beneath its icy crust. To find out if this alien ocean holds life, well need to get there, penetrate the ice shell, and navigate in an alien sea. In this episode of Explorer, well plunge headlong into the challenges of discovery on an alien world. Well meet the scientists, adventurers, and engineers who are determined to launch a mission to Europa - and follow them through the challenges, frustrations, and triumphs that come with planning a distant mission to an alien world. Through high-end CGI and quests to the edge of our planet, well go on a journey to and alien moon called Europa. To answer the basic question: Are we alone in the universe?
2010 • Astronomy