The earth is a planet that lives and constantly changes. Its emergence was a process that took hundreds of millions of years to complete. In a cosmic fog, gas and dust collated to form a flat disc. Under the influence of gravity, dust particles stuck together to form bodies that became increasingly larger and heavier and in which more and more matter was concentrated. Dust became boulders and boulders became protoplanets, the predecessors of the planets we know today. When the early solar system stabilized, the sun shone in its middle, and nine planets and an asteroid belt circled around it. One planet - earth - had a very special set of starting conditions: The distance of earth to the sun is optimal, and water is present in the form of ice, liquid and steam.