THE GOLDILOCKS ZONE
The chemical reactions that make life possible can only happen in liquid. Gas molecules are too far apart to interact, and solids can’t move around enough to mix together. That’s why water is essential. There’s no other liquid in the universe that behaves quite like it. Made from one oxygen atom and two hydrogens, water molecules have a special chemistry. They can dissolve almost anything, allowing the chemicals of life to mix and react. The Goldilocks zone is the space around a star where water can exist in its liquid form: not too hot and not too cold, but just right for life to evolve.