The Earth formed over 4.6 billion years ago out of a mixture of dust and gas around the young sun. It grew larger thanks to countless collisions between dust particles, asteroids, and other growing planets, including one last giant impact that threw enough rock, gas, and dust into space to form the moon.
Although the rocks that record the earliest parts of Earth’s history have been destroyed or deformed over time by more than four billion years of geology, scientists can use modern rocks, moon samples, and meteorites to figure out when and how the Earth and moon formed, and what they might once have looked like