In the beginning

Abstract

The Earth is old, and in its fabric is written a subtle and complex history. The oldest material ever discovered on Earth consists of a few crystals of a mineral called zircon. These crystals, found in Western Australia, are about 4.3 billion years old. Many of the elements that make up the Earth are roughly 4.6 billion years old, and the planet probably formed soon after that, although much of thç hydrogen in our water may be as old as the universe. For the first 300 million years that Earth existed there is no history recorded in our terrestrial rocks, although the Moon, meteorites and comets preserve earlier material. Some meteorites even preserve traces of events that took place before the formation of the Solar System.