Target planet selection and terraforming. (a) The objective function, used for determining the destination of life from a terraformed “parent” planet. Candidate destinations are first constrained by a maximum positional distance threshold; among these candidates, the planet closest in composition to the parent planet is chosen as the target. (b) Simulations are initialized with one origin of life, causing the initial distribution of planet compositions (seen in panel (a)) to become correlated. (c) An example of how we determine target planet composition when retaining 10% of the pre-terraformed planet composition. Note that while our simulations use a 3D space, the concept figure shows only a 2D space for clarity.