Illustration showing the stages in the formation of the Earth, up to the present day. The Earth formed 4.5 billion years ago. In the first stage seen here the Earth is already a molten ball of rock. In the early solar system it is bombarded with meteorites and comets. Earth's surface changed from molten to solid rock around 3800 million years ago and liquid water condensed on the surface. The atmosphere formed and 2500 million years ago stable continents formed.