Earth's history spans approximately 4.5 billion years, beginning with the formation of the planet from dust and gas in the solar system. Over time, the surface cooled, allowing for the creation of oceans and the atmosphere. The earliest life forms, such as simple bacteria, emerged around 3.5 billion years ago, marking the start of biological evolution. Throughout its history, Earth has experienced significant events, including the Cambrian Explosion, which saw a rapid increase in the diversity of life around 541 million years ago. Major extinction events, like the dinosaurs extinction 66 million years ago, reshaped ecosystems and paved the way for new species to thrive.