Have you ever heard of light pollution? It's the overuse of light at night. Nearly everyone on Earth has experienced it. Cities are bathed in light, but lights also encroach on the wilderness and rural landscapes as well. The International Dark-Sky Association is a leading authority on light pollution, its causes, and ways to reduce it while preserving safety and security. Check out their Web site, and their video "Losing the Dark", available to watch on Youtube and Vimeo, and downloadable for educators, planetariums, and other outreach professionals.
The Sun is a star, one of trillions of stars in the Milky Way alone. Our star has a nuclear furnace in its core, where it fuses hydrogen into helium. In the process, it gives off heat and light, just as other stars do that have the same core process.