How Cosmic Collisions Have Shaped Our Solar System

From the rocky fragments in Saturn's rings to Earth's own moon, our solar system bears signs of an ancient demolition derby. Planetary scientist Erik Asphaug describes the role of impacts in our planetary neighborhood, and looks ahead to a possible comet collision on Mars.

Source: http://www.npr.org/2013/03/29/175741693/segment-2?ft=1&f=1007

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