Show What You Know The sun is the center of the solar system. The sun’s gravity keeps Earth in its orbit, preventing it from drifting off into space. Energy from the sun allows plants to grow, reproduce, and provide us with food. Solar energy also powers the circulation of air in the atmosphere and water in the oceans. This movement provides us with weather. The position of Earth as “third rock from the sun” provides the temperatures needed to sustain life—not too hot, not too cold, just right! At Home in Space? The conditions on Earth make it the perfect place in the solar system for life to do well. But humans, by nature, are explorers. It is inevitable that some people will eventually leave Earth and set up a human colony elsewhere. But the question is where? Another planet? A moon perhaps? Another galaxy? Whatever the destination, the explorers must recreate Earth-like living conditions to survive. This includes building air-tight homes and neighborhoods, finding a place to grow food, and providing access to clean water and air. The explorers can bring some of the equipment and materials needed from Earth. But the rest has to be made onsite from available resources. Once built, a new human colony in space must be sustainable. After all, Earth might be several months or years away.