The universe contains millions of galaxies formed of thousands of millions of stars, planets, and other objects. Our solar system is made up of the sun and everything that orbits it, including planets, satellites, and other bodies. The document then describes key details about the Earth, including its three layers of geosphere, hydrosphere, and atmosphere. It also notes that the moon is Earth's only satellite, which we see in different lunar phases and which causes eclipses and tides.