Notes


 * The Solar System** is located in an outer arm of the Milky Way galaxy. This is just one galaxy of billions in the universe, and each of these galaxies contains billions of stars. The Solar System is composed of planets, asteroids, and comets that are held near by the gravity of the Sun.



The Sun is a medium-sized star that burns Hydrogen (1 proton per atom) and fuses it into Helium (2 protons per atom), in a process calle nuclear fusion. This is what creates heat and light that radiates outward from the sun.