The Precambrian Era is the least understood part of Earth history, yet it is arguably the most important. It began with the formation of Earth nearly 4.6 billion years ago, and lasted for approximately 4 billion years. During this time, all of Earth’s major systems appeared, such as the hydrosphere, biosphere, geosphere, and atmosphere. The Precambrian Earth experienced impacts by massive celestial objects, the first continents and ocean basins, mobilization of tectonic plates, an oxygenated atmosphere, and the origin and evolution of early life. Not only did life begin and survive during this challenging, harsh time period, but it thrived and continued to evolve. The evidence for the story of the Precambrian era is within Earth’s rocks. Where on Earth’s surface do you think scientists can locate rocks from the Precambrian era? How do scientists determine the age of the rocks they’re analyzing? What types of tests or analyses do you think scientists would conduct on a rock from the Precambrian era? Lastly, how does understanding the Precambrian era enhance our chances of finding another planet that could one day support life?