Good question! Stars are definitely useful for many different reasons! Let me give you a few examples… Let’s think about the star that is closest to earth: the sun. The earth’s surface gets most of its heat from sunlight. Some of the heat at the surface actually comes from deep in the earth, but most is from the sun. If the sun weren’t around, then it would be too cold for life to exist on earth. Even if heat from deep in the earth kept the surface warm enough for there to be liquid water, photosynthesizing organisms (green algae and plants) would not be able to live without sunlight. Here’s another reason why stars are useful: Most of the chemical elements on the periodic table are created in stars. Hydrogen and helium formed very early in the life of the universe, before stars had formed, but other elements are actually made in stars and supernovae when hydrogen and helium nuclei (a nucleus is the center of an atom) come together to make nuclei with more protons. Without stars, there wouldn’t be the silicon, oxygen, iron, and magnesium that make up most of earth, and there wouldn’t be the carbon, oxygen, and nitrogen that make up most of the cells of living things. There are many other reasons that stars are useful. Can you think of any?