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Planet Profusion
There are hundreds of billions of galaxies in the universe. Our solar system is located in the Milky Way Galaxy, which is 100,000 light-years in diameter. Even though this galaxy contains an estimated 100 billion stars, our solar system contains only one star—the sun. The sun, which is the center of our solar system, has eight planets and myriad dwarf planets, asteroids, meteorites, and comets orbiting it. The planets are large, nonluminous bodies that follow fixed elliptical orbits about the sun. (See the illustration above.)