At various times in Earth’s history, our planet has been a “snowball”.
At the 2012 Astrobiology Science Conference, Astrobiology Magazine hosted a plenary session called "Expanding the Habitable Zone: The Hunt for Exoplanets Now and Into the Future."
The session featured a panel of exoplanet hunters and thinkers, who held a lively discussion about some of the most important issues facing the search for and understanding of alien worlds orbiting distant stars.
Below you can find links to the first seven parts of the 10-part series along with a brief synopsis of each installment:
Hunting for Alien Worlds: A Cosmic Debate (Part 1) — In part one of this series, the panelists discussed their specialties and explained their passion for learning about alien worlds.
Hunting for Alien Worlds (Part 2): Science of Exoplanet Habitability — A panel of exoplanet scientists held a lively discussion about some of the most important issues facing the search for and understanding of planets orbiting far-distant stars. Part two of the series explores exoplanet science today.
Hunting for Alien Worlds (Part 3): The Habitability Debate — In this portion of the 10-part debate, a group of exoplanet scientists come up against the limits of figuring out whether an alien world has life.
Hunting for Alien Worlds (Part 4): 'Snowball Earth' & Earth-Like Planets — Exoplanet scientists discuss Earth's past as a way of finding more Earth-like planets in the future.
Hunting for Alien Worlds (Part 5): The Future of Exoplanet Science — Scientists discuss what the search for alien planets should look like in the future.
Hunting for Alien Worlds (Part 6): Exoplanet Missions in the Future — In part six of this 10 part series, the panelists discuss the exciting possibilities of future missions that could uncover exoplanets.
Hunting for Alien Worlds (Part 7): Moving Future Missions Forward — A panel of exoplanet scientists discusses missions to discover and characterize worlds orbiting distant stars.
Hunting for Alien Worlds (Part 8): The Danger of Crying Wolf About 'Earth Twins' — The panelists debate whether the many press releases about the possible habitability of newfound planets risk "crying wolf".