(August 2004) 1.0 The Beginning The planet Earth is approximately 4.6 billion years old. During the initial 0.7 billion years following its formation, the early Earth was heavily bombarded by solar system materials, such as comets and asteroid-sized objects. The energy released by the largest impacts was sufficient to evaporate the oceans and destroy any existing life on the Earth’s surface. The first signs of life evidenced by the fossil record came into being approximately 3.5 billion years ago [1]. Figure 1. The early Earth’s reducing atmosphere provided conditions for the formation of organic polymers from either terrestrial or extraterrestrial…