Rare Earth
- Episode aired Dec 18, 2007
- 51m
Our planet is unique within the solar system. Four-and-a-half billion years ago it had a 'twin' named Theia which was absorbed into the Earth, increasing its gravity and allowing it to form ... Read allOur planet is unique within the solar system. Four-and-a-half billion years ago it had a 'twin' named Theia which was absorbed into the Earth, increasing its gravity and allowing it to form an atmosphere. Iain travels to Meteor Crater in Arizona to explore the atmosphere's role i... Read allOur planet is unique within the solar system. Four-and-a-half billion years ago it had a 'twin' named Theia which was absorbed into the Earth, increasing its gravity and allowing it to form an atmosphere. Iain travels to Meteor Crater in Arizona to explore the atmosphere's role in protecting us from bombardment by meteorites, and finds that life on earth only prospers... Read all