Stars are massive, luminous plasma balls held together by gravity. Every form of matter we can see around us comes from the stars, without it, galaxies, solar system, and even life itself would not exist. Stars are thought to be the origin of the universe. Stars were used by human to aid in navigation, expeditions were executed using stars as areas of reference. The Sun, which is actually the closest star on Earth, is the most basic element necessary to give life on Earth.