Planets make up the environment. At the start of a new game, all the planets in the galaxy are barren. Planting seeds on a planet will allow it to regain its vitality. The number of seeds required will vary from planet to planet, with larger planets requiring a greater number of them. As more planted seeds mature, the heart gauge in the center of the planet will fill up to indicate how close to fully restored the planet is. Once the planet is completely restored, a chest will appear, and you will be able to regain health from the planet's health pool. Building a Moai Smash will refill the planet's health over time.