Stars and Planets

Stars are massive, glowing balls of hot gases, mainly hydrogen and helium, that produce light and energy through nuclear fusion in their cores. They appear as bright points in the night sky and vary in size, brightness, and color. Planets are large celestial objects that orbit stars, including our Sun; they do not produce their own light but reflect the star's light. Planets can have atmospheres, surfaces, and sometimes moons. While stars generate energy through internal processes, planets are generally much cooler and rocky or gaseous bodies that countenance the structure of solar systems.