Earth: History

The History of Earth

Earth is believed to be 4.5 to 5 billion years old and was probably formed along with the rest of the solar system when a dusty nebula coalesced into distinct planetary bodies. Since its creation, Earth has endured numerous transformations and catastrophes, geological and biological alike. Though life on the planet arose roughly 3.5 billion years ago, humans appeared only relatively recently. What planet may have long ago collided with Earth, ejecting enough material into space to form the Moon? More...