This article has been reviewed according to Science X's editorial process and policies. To model water on Earth, you need incredibly high-resolution data across an immense expanse, and you need modeling sophisticated enough to account for everything from snowcaps on mountains to soil moisture in valleys. Now, scientists have made a tremendous step forward by building the most detailed models created to date. A digital twin of the Earth, constantly updated with new data, would allow us to simulate best and worst-case scenarios,