In our solar system, Sun is the source of heat and light. This heat and light radiated in our solar system and reach upto the planet and their moons. Our life is impossible without these two things. Without heat the earth become the sphere of ice. Plants will be unable to grow as they get their food through the process of photosynthesis that required sun light. Without light, the earth will go in dark. The perfect distance from the Sun makes life possible in this planet as it is getting the exact amount of heat and light that is required to keep the temperature of the planet for living.