Earth's Twin

Billions of years ago, Earth collided with its twin planet Theia. The impact and resulting geophysical changes prepared Earth for complex life. Physics - Our Solar System - Learning Points. 4 billion years ago Earth had a twin called Theia. Theia was about the size of Mars, and was on a similar orbit to Earth. As the force of gravity between Theia and Earth grew, they pulled each other off course and collided. Following the collision with Theia, Earth grew large enough to sustain an atmosphere. A Twig Context Film. Reinforce and extend the learning required by the curriculum. Twig’s context films show abstract concepts in action in the real world.